here's the 'best' method --
1. stop charging. period. no exceptions.
the interest is killing you and you're paying interest on everything you charge even though the merchant has already paid interest for the first 45 days.
2a. pay the minimum on all three cards EVERY month,
2b. PLUS put as much added money as you have available toward the one with the lowest balance. do this until that one is paid off.
3. thereafter, use the paid off card ONLY if you absolutely must and then ALWAYS pay it off that month. You want to NEVER pay any interest on anything you charge.
4. repeat steps 2a and 2b for the card with the next lowest balance.
5. repeat step 4 for the last card.
6. then pay off all the cards every month.
most people have a huge psychological problem with credit cards -- they don't get much pleasure out of paying off but get a lot of pleasure out of buying today.
this system hurts [step 1.], which is unavoidable. And, by paying off the smallest card first [steps 2a and 2b] it gets you to the psychological good part [the feeling of relief because that one is GONE] as soon as possible.
University researchers have shown that people will promise to pay as much as double the cash price for something if they can put the payments off via a charge card. That's how you get in trouble. If you can't afford to pay cash today -- you can't afford it. period.
so step one has to be to stop charging. charge nothing at all. if you can't pay cash right now, don't buy it.