Next-purchase coupon: how to design it so customers come back

Acquiring a new customer costs advertising, time and, often, a welcome discount. If they don't come back after that first purchase, you have paid all of that for a single order. Most stores have a huge base of one-time customers and a minority who buy again and keep the business going.

The next-purchase coupon targets exactly that step: the customer who has just paid gets a concrete reason to come back, with an expiry date. Well designed, it is one of the most profitable promotions there is. Badly designed, it is a discount handed to people who would have come back anyway.

Why the second purchase is the hard one

On the first purchase the customer had a need and found you. On the second they already have what they wanted, need nothing urgently and probably won't remember your store's name in three months. Whoever makes a second purchase is far more likely to make a third: that is where the habit forms.

That is why the time to issue the coupon is right after the first order is paid, while the experience is fresh and the customer is watching your emails because they are waiting for their parcel.

How much to discount

The amount comes from your margin, not from what competitors do. A simple calculation: if your average order value is €60 with a 35% gross margin, each order leaves about €21. A 10% discount on the next €60 order costs €6 and leaves you €15. A 25% discount leaves you €6, which no longer covers shipping or picking.

The three usual formats have different effects:

• Percentage: it scales with the order, so it is wise to set a cap (15% up to €30, for example) so that a large order doesn't eat your margin.
• Fixed amount: easier to understand ("€10 off your next order") and easier to control, but it needs a minimum spend, or people will buy an €11 product for €1.
• Free shipping: works very well when shipping is the main objection and the average order value is close to the free-shipping threshold.

A good practice is to scale the coupon according to what the customer has just spent: a small order gets a modest coupon and a large order a more generous one. That way you reward the spend and don't give everyone the same thing.

How long it should last

A coupon with no expiry, or a year to use it, gets forgotten in a drawer. A short expiry is what turns it into a nudge: two to six weeks is a reasonable range in most sectors. Match it to your repurchase cycle: for consumables that run out every month, one month; for fashion or gifts, a little longer.

A reminder a few days before expiry usually recovers a significant share of the coupons that would otherwise have been lost. One reminder, not three.

Restrictions that prevent nasty surprises

1. Single use and tied to the customer. If the code is generic, it will end up on a coupon website and be used by people who have never bought from you.
2. Not combinable with other promotions, unless you decide so on purpose.
3. Issued on payment, not when the order is placed. A bank transfer that never arrives or a rejected cash-on-delivery parcel should not generate a coupon. And if the order is cancelled or refunded, the coupon is revoked.
4. One per order, even if the order changes status several times.
5. No coupon for orders that already had a promotion, if you don't want to stack discounts.
6. Guests: a customer without an account will make their next purchase under a different customer record, and a coupon tied to the first one won't work for them. Either invite them to create an account or don't issue a coupon.
7. Catalogue exclusions: products with minimal margin, gift cards or items already on sale.

How to get it to the customer

The coupon has to be where the customer will see it when they think about coming back:

• In the order confirmation or in a separate email straight afterwards, with a button that takes them to the cart with the code already applied.
• In "My account", with the code and the time left.
• In an on-site notice when they come back while logged in.
• In the reminder before expiry.

Emailing the coupon to an existing customer is a commercial communication. The LSSI (Spain's Information Society Services and E-commerce Act), in its article 21, allows it without prior consent when there is a contractual relationship and similar products are offered, provided every email includes a simple way to unsubscribe. If the coupon goes inside the confirmation email, that email now carries commercial content and must be treated in the same way.

How to tell whether it works

The obvious metric is the redemption rate: coupons used divided by coupons issued. But a high redemption rate proves nothing if the people using them would have come back anyway. The questions that matter are different:

• Attributed revenue: the total of orders with a coupon and how much discount you granted on them.
• Time to second purchase: if customers come back sooner with the coupon, it is speeding up repurchase.
• 90-day repeat rate of customers with a coupon compared with the rate you had before switching it on.
• Results per tier: sometimes the small coupon is barely used and the large one is, or the other way round.

If you have enough volume, the clean test is a control group: for a few weeks, part of the orders receive no coupon. Comparing repeat purchases in the two groups tells you how much the coupon really sells, not how much discount you have handed out.

Common mistakes

• A single code for everyone, shown on the order confirmation. Within a week it is on the internet.
• Coupons issued on orders that are later cancelled.
• An uncapped percentage in a catalogue with expensive products.
• A one-year expiry: nobody remembers it.
• Measuring only redemptions, without checking whether repeat purchases have gone up.
• Changing the rules every month, so there is no way to compare.

Checklist

• Work out the maximum discount your margin per order can absorb.
• Define tiers based on the first order amount, with a cap and a minimum spend.
• An expiry that matches your repurchase cycle and a single reminder.
• A unique, single-use coupon tied to the customer and issued on payment.
• Automatic revocation if the order is cancelled or refunded.
• An unsubscribe link in every email that carries the coupon.
• Measure redemptions, attributed revenue and 90-day repeat rate; with a control group if you can.

How to do it in PrestaShop

RKR Offer Next Buy creates a unique coupon for each order that reaches a paid status, with tiers based on the amount spent (percentage, fixed amount or free shipping, each with its own minimum spend and validity period), and revokes it if the order is cancelled or refunded. It sends it in an email with a button that takes the customer to the cart with the code applied, shows it in "My account" and in a banner, reminds the customer before it expires and gives you the redemption rate, attributed revenue and results per tier. If you would rather have the coupon travel inside the order emails alongside recommended products and banners, RKR Ofertas en emails transaccionales generates a single-use coupon per order and measures opens, clicks, redemptions and revenue.