> don't understand how standard rates are sky high while promotional rates are near the rock bottom. Promo rates are the bank's marketing department paying to

> don't understand how standard rates are sky high while promotional rates are near the rock bottom. Promo rates are the bank's marketing department paying to hook in the card holder on the probability that they will use the card for a long time. The standard rate largely factors in the cost of doing transactions (shared with the merchant percentage) and covering the risk of default. The 14-18% rates go to 24%+ if the card holder moves to a higher risk class (recently defaulted on another card, missing payment dates, etc).