Packing Slips, Inserts and Samples: How to Add Marketing Materials to Orders Without Slowing Dispatch

To add packing slips, inserts and samples without slowing dispatch, give every item a clear job, check each marketplace's rules, and let the warehouse system decide which order gets which insert. Hold inserts and samples as counted stock, check what they do to parcel size, and pilot before scaling.

A parcel is one of the few marketing channels a brand fully controls. The customer has paid, the box is open, and a well-judged card or sample costs far less than winning a new customer. The difficulty is doing it at volume. Every extra item is another thing for a packer to find and count, and another chance for an order to go out wrong. This guide covers how to plan inserts so they help rather than hinder, the Amazon and UK rules that apply, and what to ask a fulfilment partner. If you would rather hand the work over, our kitting and branded insert service covers it from component storage to dispatch.

Packing Slips, Inserts and Samples: What Each One Is

These three items do different jobs, and a warehouse handles each one slightly differently.

• Packing slip: a document printed for each order listing what is in the box. It helps the customer check the delivery and handle a return. A branded slip adds your logo, a returns note or a short message.
• Insert: any printed item added to the parcel, such as a thank you card, discount leaflet, care guide, referral card or catalogue.
• Sample: a small free product, such as a sachet or miniature, added to introduce a range the customer has not tried.

A packing slip is generated per order. Inserts and samples are physical stock that has to be stored, counted and picked, which is where most of the operational risk sits.

Decide What Each Insert Is For

Every insert should have one job you can name. A thank you card builds loyalty. A discount leaflet drives a second purchase. A sample introduces a new product to someone who already trusts you. A care or sizing guide reduces avoidable returns. A branded packing slip makes a plain document look like part of the brand.

If you cannot say what an item is meant to change, leave it out. Each one adds handling time and cost, and a box stuffed with paper feels less considered, not more. One or two items with a single clear call to action will usually do more than five.

Amazon Insert Rules and UK Review Law

Amazon allows inserts, but it limits what they can say. Amazon's own guidance for sellers on product inserts lists what is fine and what is not:

• Allowed: thank you notes, your brand story and values, care instructions, assembly guides and tips for using the product.
• Not allowed: asking for positive ratings or specific feedback, offering coupons, free products, refunds or payment in return for a review, and asking customers to contact you outside Amazon's Buyer-Seller Messaging.

A neutral request to leave a review based on the customer's experience is acceptable on Amazon. Amazon's seller rules also bar marketing messages and calls to action that lead customers to leave Amazon, so keep website addresses, email addresses and QR codes pointing elsewhere off any Amazon insert. Amazon updates its policies, so check the current position in Seller Central before printing.

The same caution applies to orders from your website. Under UK consumer law, fake reviews and reviews that hide an incentive became a banned practice in April 2025, and the CMA guidance on online reviews explains that a review written in exchange for money or another benefit must not hide that fact. A card offering a discount for a five-star review is a risk on any channel, not just Amazon.

The practical answer is a separate insert specification for each channel. A single card used on every order is the easiest way to breach a marketplace rule by accident. This is general guidance; check current marketplace terms and take advice if a campaign sits close to the line.

Make Inserts Rule-Based, Not Manual

Inserts slow dispatch when packers have to make decisions. If someone has to read an order note to know whether a sample goes in, errors follow. The fix is rules held in the warehouse system, so the pack station shows exactly what to add.

Typical rules look like this:

• Add a sample to any order over a set value.
• Add the care guide only when a particular product is in the order.
• Use the branded slip for website orders and a plain insert set for Amazon orders.
• Add a welcome card to a customer's first order only.

For larger campaigns, ask for each insert to be scanned at the pack station so the system records that it went in. That gives you a record to check against when a customer says their discount card was missing.

Treat Inserts and Samples as Stock

Printed materials and samples are inventory. They need their own SKU, a storage location near the pack stations, counts and reorder points, just like products. Running out of a leaflet mid-campaign either stops dispatch or sends orders out without it, and neither is acceptable.

Ask for insert quantities to sit in the same system as your products, with alerts when stock runs low. Allow for print lead times when you plan a campaign, and give the warehouse notice before artwork changes so old versions can be removed and not mixed in with the new. Samples with a shelf life also need batch and expiry tracking, so the oldest stock goes out first and nothing out of date reaches a customer.

Check What Inserts Do to Parcel Size and Postage

A sample or a thick leaflet can move a parcel into a more expensive postage band. Royal Mail's size limits for a Large Letter are 35.3cm by 25cm by 2.5cm and 750g; anything thicker or heavier is a Small Parcel, which costs more. For a brand shipping flat items such as socks, cards or cosmetics, a sachet that adds a few millimetres can tip thousands of orders over the 2.5cm limit.

Before launching a sampling campaign, pack a finished order with the insert included, then weigh and measure it. Also check any labelling and shelf life rules for free samples of cosmetics, supplements or food with your own advisers before they go in a box.

Measure Whether Inserts Are Working

An insert you cannot measure is a cost you cannot justify. Give each insert its own discount code or landing page, so redemptions can be traced back to the campaign. Where you can, run the insert on some orders and not others for a few weeks, then compare repeat purchase rates between the two groups. Track what each insert costs to print, store and add, and set that against the extra revenue it brings in.

Questions to Ask a 3PL Before You Add Inserts

• Can inserts be added by rule, based on order value, product, channel or first order?
• Are inserts charged per insertion, included in the pick fee, or quoted as a project?
• How is insert stock counted, stored and replenished, and will I get low-stock alerts?
• How is an artwork change handled, and how is old stock removed?
• How long does it take to set up a new rule, and who does it?
• Are pre-built kits that include inserts tracked as their own stock?
• What checks happen before the parcel is sealed, and how are mistakes reported?

Our guide to how value-added fulfilment supports launches, promotions and seasonal campaigns covers the planning side, and the article on custom packaging and unboxing experiences covers the brand side.

How Fulfil with Synergy Handles Inserts and Samples in Northampton

Fulfil with Synergy is a founder-led UK third-party logistics (3PL) provider that runs multi-channel, retail and Amazon Seller Fulfilled Prime fulfilment for growing and household brands from purpose-built facilities in Northampton. It combines AutoStore automation and the RedPrairie Dispatcher warehouse management system with high-touch services such as kitting, bonded warehousing and returns management. A team of over 280 fulfilment specialists works seven days a week.

Branded inserts, custom messaging and sustainable materials are part of the kitting service, and the work runs in-house alongside standard pick and pack. The RedPrairie Dispatcher warehouse management system gives real-time stock visibility down to unit, SKU, batch and location, a time-stamped, user-tagged audit trail of every stock movement, and exception handling that flags issues before they cause delays. That matters for inserts: leaflets and samples can be counted and located like any other stock, and batch-level visibility helps with samples that have a shelf life.

For Amazon sellers, the system can list multiple virtual bundle SKUs through Seller Fulfilled Prime and break each bundle into its components at pick and pack, so a bundle does not have to be pre-built. For campaigns, the range runs from a limited-edition influencer drop to 20 recipients up to monthly subscription boxes, and the value-added services team carries out quality control at AQL or 100% inspection levels. To scope a job, send some video, samples or images of what you want packed and the team will talk it through and quote within hours. For a wider view, see how UK 3PLs compare on value-added services.

A Launch Checklist for Inserts and Samples

1. Write down what each insert is meant to achieve and how you will measure it.
2. Check the rules for each marketplace and create a separate insert set per channel.
3. Finalise artwork, then print enough for the whole campaign plus a buffer.
4. Weigh and measure a finished parcel with the insert included.
5. Agree the rules for when each item is added, and who sets them up.
6. Confirm how insert stock is counted, located and reordered.
7. Run a small pilot, check the first parcels yourself, then scale.

FAQ

Can I put marketing inserts in Amazon orders?

Yes, within limits. Amazon allows thank you notes, brand story, care instructions and usage tips, and a neutral request for a review based on the customer's experience. It does not allow asking for positive reviews, offering coupons, free products or refunds in return for a review, or directing customers to contact you outside Buyer-Seller Messaging. Leave website addresses, email addresses and QR codes that send customers away from Amazon off the card. The safest set-up is a dedicated Amazon insert, separate from the one used on website orders, and a check of the current Seller Central policies before each print run, because the wording does change.

Do inserts slow down dispatch?

Not if they are added by rule and held as tracked stock. Delays come from packers making decisions, such as reading notes to work out which leaflet goes in, and from inserts running out mid-campaign. When the warehouse system decides which order gets which insert and shows it on screen, the packer follows an instruction rather than making a judgement. Keep inserts near the pack stations with their own location and reorder point, avoid more than one or two items per order, and pilot a new insert on a small batch first, checking the first parcels yourself so any problem is fixed before the full campaign goes out.

Should a packing slip be branded?

For orders placed on your website, a branded slip is a cheap way to make the parcel feel like part of the brand. Keep the core order details clear: order number, items and quantities, and how to return something. A short thank you line and a returns note usually work better than heavy design that uses extra ink. For marketplace orders, follow the marketplace's own approach and avoid anything that sends customers elsewhere. For gift orders, a slip without prices saves an awkward moment for the recipient, so check that your platform and fulfilment partner can print one when a customer ticks the gift option.

Can samples affect my courier costs?

Yes. A sample adds weight and thickness, and either can move a parcel into a more expensive band. With Royal Mail, a Large Letter must be no more than 2.5cm deep and 750g, so a sachet added to a flat item can turn it into a Small Parcel. Carrier pricing for larger parcels also depends on size and weight. Before launching a sampling campaign, pack a finished order with the sample included, weigh and measure it, and price it with your carrier. If it tips over a band, choose a flatter sample, use it only on orders that already ship as parcels, or limit it to orders above a set value.

Are inserts usually charged per insertion by a 3PL?

It varies by provider, so ask for it in writing. Some 3PLs include one insert in the pick and pack fee, some charge a small fee for each item added, and larger or more complex campaigns are often quoted as a project. Insert stock may also attract a storage charge. When you compare quotes, ask what happens when an order needs two or three inserts, whether rule set-up and artwork changes are charged, and how mistakes are handled. At Fulfil with Synergy, send video, samples or images of the job and the team will talk it through and quote within hours.

Inserts and samples work when they are planned like any other stock and added by rule, not by memory. If you want inserts that do not slow your orders down, talk to Fulfil with Synergy about how to set them up.

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