Checkout: Discount Coupons
Discount Coupons in the WordPress Shopping Cart plugin allow you to issue coupons that may be redemed by a shopper in order to apply a specific discount to the order.
Coupons can redeemable be for a fixed price i.e.$5.00 or for percent value of the purchase price i.e. 10%.
There is a built-in coupon code generator as well to generate random codes. You can also give coupon codes an expiration date and specify how many times a coupon code may be used globally.
Coupons may be switched of or dicontinued by you as the administrator. To turn off discount coupons on the site as a whole, go to Checkout > Configuration > Discount Coupons in your WordPress dashboard where you can turn it off.
Start by adding a discount coupon.