SimpleCart 2.5 introduces more control over the way discounts and fixed price coupons are handled.
By default, coupon codes are considered discounts. The value of coupon codes is added to the discounts total and reduced the price that way.
It's also possible to configure SimpleCart to treat fixed-price coupon codes as credit. This changes how the price reduction is applied to an order, also in regards to taxes.
By default (including before 2.5), coupon codes are considered a discount. Discounts are calculated, and the total is reduced, before taxes are calculated.
Coupons as Credit
When setting the
simplecart.fixed_price_coupons_are_discounts system setting to no, fixed-price coupons will be treated as pre-paid credit. Discounts are still calculated before the tax, but the coupon discount is applied after the taxes are added.
In this case the coupon is basically treated like a (partial) payment
Discounts and Coupons
By default, you can't use coupons and other discounts (sale prices, user(group) discounts) together. Set
simplecart.allow_discounts_and_coupons to yes to allow both coupons and other discounts at the same time.