I have $8,000 on credit card A and $2,500 on credit card B. Both have about the same APR. Credit card A I never use and am just working to pay off the balance. Credit card B we use at Costco (it's the only cc they take) so it seems like no matter what it is always at about $2500. My question is I want to use my tax return (about $2,500) to put to one of these credit cards. Do I pay off B or bring down the balance of A. Advice please?