A coupon is a document, usually a ticket, which can be exchanged for a rebate or a financial discount when you purchase goods or services. Coupons are usually issued by products' manufacturers or by retailers and can be used in retail stores or online. Free coupons are part of sales promotion. You can find coupons in your mail, newspapers, magazines, and, of course, on the Internet.

The first coupons were issued by the Coca-Cola Company in the end of 19th century. Today almost every company uses discount coupons on products or services. Increasingly, this is thanks to online shopping. More and more people every day purchase goods online. And companies started providing more and more online coupons such as online discount, free shipping, free giveaways, and first-time consumer coupons.

Online coupon codes, promotional codes, discount codes, key codes, voucher codes, shopping codes, promo codes and some others are referred to Internet coupons by online retailers which are trying to encourage consumers to buy particular product or to choose the specific retailer. Be aware that coupons may or may not reduce the sales tax which depends on the jurisdiction and is determined by a coupon sponsor. You should also pay attention on coupon protection from fraud such as ID number, unique barcodes etc.