Voucher codes can be referred to by a variety of names. A few of these names consist of "key codes" or "voucher codes" as well as "promo codes" or "source codes." In the uk these codes are often referred to as "buying codes" or "promotional codes" and there are a few other variations as well.

These type of code tend to be basically just an easy method of supplying a discount or maybe some other support for instance free delivery to the buyers who are thinking about purchasing. Many bonus coupon codes have a particular percentage discount calculated using the companies general profit margin, where a free offer code might be restricted to just one use for each customer percentage discounts are often re-usable because, simply by their nature, the more that is bought the higher the overall profit even with the discount applied.

While the buyer will get something out from the usage of a coupon code (because they are able to make the most of a promotion) the provider of the code gets a lot more than just an order from the customer, while the customer is enjoying feeling a little special with their "exclusive" discount the company that has made the code available has likely spun out several codes to different sources. This tactic allows the company to track which customer uses which code which in turn allows the marketing department to accurately track which promotions and places are best to place their codes. Some marketers have even been known to purposely "leak" a code to get attention.

So many companies that trade online offer coupon codes. Everyone from the big names players such as Amazon to smaller merchants turning over a few hundred pounds a week. Coupons codes have become so widely used online that most ecommerce checkout solutions feature the ability to use coupon codes as standard.

The first coupon codes were seen in the early 80's and originated in the mail order industry by way of direct mail promotions

Customers of larger online etailers are so used to using coupon codes and so appreciative of their value that they often go out searching for them before going through the online checkout, this can quite often turn up a 10% or more code which can be used to save significant money on a high value order.

Coupon codes are distributed by email, via forums, on specific voucher code websites and by way of affiliates. While some companies do offer exclusive discounts that they only want certain people to use they often hope that their codes will go viral meaning they spread across the web and are picked up by people who they have not been in direct communication with. Where a code is genuinely supposed to be exclusive and not just appear exclusive but actually be restricted i its usage it is fairly easy for the marketing team at the issuing company to lock the code down.