Offers with caps
An uncapped offer has one price: whatever the biggest cart decides. Caps flip that — the offer states in advance the most it will ever give, so you can advertise generously and spend precisely. PromoLock has five caps, each bounding a different thing. This playbook covers the flagship construction first, then the rest of the toolbox.
The flagship: XX% off up to $YY, over $ZZZ
Section titled “The flagship: XX% off up to $YY, over $ZZZ”A huge-feeling headline whose real payout you fixed in advance:
Get 40% off, up to $30, on orders over $150.
Sounds like a blowout; pays out 20% at best. All three numbers come from your store’s average order value (Shopify admin → Analytics; say it’s $70):
| Number | Rule of thumb | Example (AOV $70) |
|---|---|---|
| Min spend | 1.5–2× AOV — forces an extra item into the cart, still feels reachable. | $150 |
| Cap | What a qualifying order should really cost you: 15–20% of the min spend. | $30 |
| Headline % | Roughly double your real rate, rounded to a dramatic number. | 40% |
Because 40% of $150 is $60 and the cap is $30, the cap kicks in on every qualifying order — nobody ever receives 40%:
| Cart | You pay | Effective rate |
|---|---|---|
| $120 | doesn’t qualify — customer adds an item | — |
| $150 | $30 | 20% |
| $200 | $30 | 15% |
| $300 | $30 | 10% |
Flat $30 per redemption, minimum $150 in revenue, advertised at 40%. Meanwhile the same headline with no minimum pays the full 40% on every small cart that was checking out anyway — the subsidy this construction exists to avoid.
Build it: Code discount → Condition: Cart subtotal · Greater than · 150 → Order discount · Percentage off · 40 with Max discount amount 30 → tick Cap total discount amount 30 in SafeGuards as the backstop → Combines with all off → market it with all three numbers visible.
The rest of the toolbox
Section titled “The rest of the toolbox”Different offers leak differently — pick the cap that bounds your offer’s failure mode.
Quantity limit — “per customer” without saying it
Section titled “Quantity limit — “per customer” without saying it”Where: a product discount’s Quantity limit field. Caps how many units per line get the discount.
30% off hoodies — up to 2 per order. A reseller loading 40 hoodies into a cart gets the discount on exactly 2. The offer stays attractive for humans and useless for bulk-buyers, with no rules or fraud tooling involved.
Item limit + Applies to — the “cheapest item” family
Section titled “Item limit + Applies to — the “cheapest item” family”Where: a product discount’s Applies to select (All items / Cheapest / Most expensive) plus Item limit.
Buy 3, cheapest one 50% off — Applies to: Cheapest, Item limit: 1, with a Cart quantity · Greater than · 2 condition. The classic bundle-driver, and the cap is structural: however big the cart, exactly one line is ever discounted. Flip to Most expensive for premium-pushing offers where the discount should reward the big purchase, not the sock.
Max per item — tiers that can’t be gamed by price
Section titled “Max per item — tiers that can’t be gamed by price”Where: a product discount’s Max per item money field (percentage discounts).
20% off everything in Apparel, up to $25 per item. The $500 designer coat gets $25 off, not $100. Percentage offers on catalogs with a wide price spread need this — the cap keeps the offer’s cost proportional to your typical item, not your most expensive one.
Cap total discount amount — the ceiling over everything
Section titled “Cap total discount amount — the ceiling over everything”Where: SafeGuards → Cap total discount amount. One number that bounds the whole discount — every tier, every group, every part — trimmed proportionally if the parts add up past it.
This is the cap to set even when you think you don’t need one. Tiered offers, multi-group offers, anything with several moving parts: the global cap is what guarantees the parts can never compound into a number you didn’t sign off on. The tiered discount guide uses it exactly this way.
Choosing quickly
Section titled “Choosing quickly”| Your offer | The cap that bounds it |
|---|---|
| Big headline percentage | Max discount amount + min-spend condition (the flagship) |
| Category/collection percentage | Max per item |
| Free/discounted item promos | Applies to + Item limit |
| Anything bulk-buyable | Quantity limit |
| Anything with multiple parts | Cap total discount amount — always |
Pitfalls
Section titled “Pitfalls”- Min spend at or below your AOV on the flagship — you’re subsidizing orders that were already happening. Stay at 1.5× or above.
- Stretching the headline past ~2–3× the real rate. A 60% headline that pays 10% reads as bait at checkout, and bait converts once.
- Hiding the caps from marketing. “Up to $30”, “max 2 per order” — state them wherever the headline appears; a customer discovering a cap at checkout is a support ticket.
- Leaving Combines with on. A second code stacked on top un-caps everything. Keep the flags off and the stacking lock on.