Okay, American Express has a commercial selling their savings accounts. The idea is that one percent of your purchases are put into a high yield savings account. The APR for the card is between 13.99% and 15.99%. So, to place $100 in the account, you would need to spend $10,000. That $10,000 at even the lowest of those interest rates would feel like murder. They do have a grace period of 30 days. However, people who keep from overspending are the kinds of people who are smart enough to seek out the best high yield savings accounts.