Promo Codes
In order to allow tracking of marketing campaigns and other promotional efforts, user defined promo codes can be passed in the querystring to the ordering pages, and will b tracked on the order when it is completed. The Promo Code Report can then be used to generate statistics on these promo codes, giving information on the number of invoices and the revenue generated for each promo code.
Use of promo codes is simply a matter of adding PROMO=XXXX (where XXXX is the code, up to 50 characters) to the querystring of your buy now links. There are no restrictions on what your promo codes can be named. Beware of using special characters, however. If these are necessary, be sure to URLEncode the promo code value in the buy now link.