Common terms:
* Coupon: This is the most common and general term.
* Voucher: This term is often used interchangeably with "coupon" but can sometimes imply a slightly higher value or a specific purpose.
* Discount coupon: This emphasizes the purpose of the coupon, which is to provide a discount.
* Promo code: This term is more common for online purchases and refers to a code that is entered at checkout to receive a discount.
Less common terms:
* Bargain ticket: This term is used for coupons that offer a discount on tickets to events or performances.
* Rebate coupon: This term is used for coupons that offer a refund after a purchase.
* Gift certificate: This term is used for coupons that are redeemable for goods or services at a specific store.
Ultimately, the best term to use will depend on the specific context.