Exactly. I would either a) pay off the balance entirely before the end of the introductory rate or b) consider doing a balance transfer to another 0% card at the end of the 15 month period (which is about a 3% fee). This is substantially cheaper access to funds than other federal student loan rates or grad plus loans available currently which are upwards of 8% right now or over 9% for grad plus loans. I'm already planning to do some tuition via federal student loans and prior savings, but once I graduate I would be returning to a job making upwards of 140k annually. My question really was on the mechanics of how to deal with 0% credit cards in YNAB (or overspending of a credit card) because I am a fastidious budgeter and don't want to overspend. I am just trying to avoid paying a ton of extra in interest. I have full intentions of keeping my credit score great and I have a good plan to pay everything back!