if you transfer $5000 to the card with the 2.99% interest for 6 months and no balance transfeer fee, and you pay $300 per month, you will pay $64 in interest for those 6 months and your ending balance will be just under $3,300. if the interest then goes up to 12.99%, you will pay off the balance in full (at $300 per month) in another 12 payments and your total interest paid will be $290. If you do a balance transfer to a card with a 5% balance transfer fee and 0% interest, the fee will be $250 and the balance will be paid off in the same 18 month timeframe. So look at the exact terms you can get, and decide what's cheapest.