I find it easier to pick your lowest debt card and pay it off...then pay the next lowest off with the addition to the amount you were paying off the lowest. IE

BEFORE:
$340 balance card.......$15 a month
$500 balance card.......$35 a month
$800 balance card.......$50 a month

AFTER:
$340 card is paid off
$500 balance card.......$35 a month + $15 a month^^^^
$800 balance card.......$50 a month

Do that untill all of you debt is gone. You will not feel a difference in your budget (YOU SHOULD HAVE ONE!!!) and you will get you debt paid off sooner