When you sign up to an affinity credit card, a certain amount will be donated to the organisation, and then a nominal amount for every transaction you make thereafter.They will usually give you a discount on your first purchase, but typically have high interest rates of around 30%, which make them an expensive form of borrowing.  Store cards are similar to credit cards, but are only valid for use in the shop they are affiliated with. Charge cards are similar to credit cards and allow you to buy products on a period of interest free credit. However, the balance must be paid in full each month.