What APR is telling you
A 24% APR on a $1,000 credit card balance costs you roughly $240 a year in interest if you carry the balance for the full year. Lower APR = cheaper borrowing.
APR vs interest rate
For credit cards they are usually the same. For loans, APR often includes fees, so it is a more honest comparison number between two offers.
How to avoid paying it
Pay your full credit card balance every month. When there is no leftover balance, most cards do not charge interest at all.
Example
Card A has a 19% APR. Card B has a 29% APR. On a $2,000 balance carried for a year, Card A costs $380 and Card B costs $580 — a $200 difference for the same purchase.