Your delivery fee survives the discount code, so say so in the email

The email goes out on a Tuesday: 20% off the print run, code SPRING20. By Tuesday evening you have four replies that all say roughly the same thing. I put the code in and it still came to more than I expected. Nothing is broken. The code took 20% off the print, and the £4.50 you set for postage stayed exactly where it was, because postage is a cost you actually pay to a carrier rather than a margin you can hand back. The problem is not the maths. The problem is that the email said 20% off and the buyer did the sum in their head before they reached the checkout.

Why this particular surprise stings more than it should

A buyer who reads "20% off" builds a number before they click. If the item is £30, they have already decided they are spending £24. When the page says £28.50, the gap is only £4.50, but the feeling is not about £4.50. It is about being told one thing and shown another, at the exact moment they were about to hand over card details. That is the worst possible moment to introduce an unexpected number, and it is why postage surprises cost more sales than their size suggests.

The honest complication is that you cannot fold postage into the discount without eating it. If you sell a £30 print with £4.50 postage and someone uses a 20% code, discounting the postage too would take £6.90 out of your pocket instead of £6.00, and the £4.50 still has to be paid to whoever carries the parcel. Multiply that across a busy week and the difference is real money. So the platform behaviour is right, and the fix belongs in your writing rather than in your settings.

The second complication is that postage is genuinely variable and your flat fee is not. store.fan collects a full delivery address — 250 countries, official region lists for 33 of them, districts in Turkey — and then applies the single flat fee you named. That keeps the checkout simple and predictable for the buyer. It also means you are the one absorbing the difference between a domestic parcel and a heavier international one, which is a pricing decision you should make deliberately rather than discover in a fortnight.

Where the numbers actually come from

Most creators handle postage in the way that causes the most support email: quote a total in the caption, work it out again by hand when the order arrives, and hope the two agree. Here is the same job in a store.fan checkout, where the fee is part of the order rather than an afterthought.

Writing the email so nobody has to do arithmetic

The whole fix is three sentences placed where people are already looking. Not in a footer, not in an FAQ link — inside the paragraph where you introduce the code, because that is the moment the buyer starts predicting their total.

A worked example: a £30 print, a 20% code and a flat fee

You sell a signed A3 print at £30 and you have set a flat delivery fee of £4.50. You are running a code at 20% for one week. The correct sentence in the email is: the code takes £6 off the print, postage is a flat £4.50, so you will pay £28.50 in total. That single line does more for your conversion rate than another paragraph about the paper stock.

Now imagine 40 of those orders. That is £960 for the prints after the discount and £180 of delivery fees, all of it landing in your own Stripe account with 0% taken by store.fan and Stripe's own card processing fees applied as usual. If your real postage cost averages £4.10, you are roughly square on delivery, and the discount came out of margin where you meant it to. Those figures are an illustration of the arithmetic, not a projection of your sales — the useful part is that you can run the same sum with your own numbers before you decide the fee.

The mistake most people make

The mistake is quietly refunding the postage to whoever complains. It feels like a two-minute kindness, and it turns your delivery fee into a fee that only the polite people pay. Worse, it teaches you nothing: the next email goes out with the same missing line and the same four replies. If the fee is genuinely too high, lower it for everyone and say so. If it is right, defend it in one plain sentence — people accept postage costs money, they simply refuse to be surprised by it. The same instinct is worth applying to your discount codes generally: fix the copy, not the individual complaint.

Nobody has ever cancelled an order because postage cost £4.50. They cancel because they expected £24 and the screen said £28.50 with no warning. Put the number in the sentence with the code, and the whole category of complaint disappears. If you want the fine print on how orders and fees behave, it is all set out in the FAQ.