One of the best ways to approach the opportunity cost of debt is to consider your interest rates as “potential rates of return.” In other words, if you had to choose between putting $100 per month toward a savings account paying 2% and a credit card charging you 15%, you should pay down the credit card. Even though you won’t earn the 2% annually on your $100, you avoided paying 15% on the same amount. For the savings account to make more sense, it’d have to have a higher interest rate than your credit card. In short, this means paying off a 15% credit card is roughly equivalent to earning 15% on your money!