The three types
- Percent (%): a whole percentage (0 to 100) off the cart.
- Fixed Amount (Cart): one amount off the whole cart, never more than the cart.
- Fixed Amount (Per Product): the amount off each unit, capped at that unit's price, so three items give three times the discount.
There is no free-shipping coupon and coupons do not stack: one code per order.
The form
Coupon Code is uppercased and unique (up to 50 characters). Min Order is compared with the cart's item subtotal before shipping, tax and the discount. Usage Limit is the total number of uses across the store (blank is unlimited). Start Date and End Date are optional; the end date runs to the end of that day. The Active switch turns a code on or off.
The form has no per-customer limit, maximum-discount or exclude-sale-items fields, and no product or category restriction, so every coupon applies to the whole cart.
Usage counting
A use is counted when the order is placed and released if the order is failed or cancelled, or if an unpaid gateway order is older than 60 minutes. Bank-transfer orders hold their use until you act. Refunded orders still count.
When a coupon is invalid
In the cart a buyer sees "That coupon can't be applied." At payment, the order is refused with "This coupon can't be applied to your order — it may have expired or reached its usage limit. Remove it and try again." An invalid coupon never lets the order go through at full price.
Editing
Clearing the usage limit or a date on an existing coupon removes it. Dates show as the local calendar day you chose.