Here’s a sampling of some attractive credit card deals available — and how easy it is to lose them.

• Discover deal: No interest for the life of the loan.

Catch: After six months, you lose the rate if you do not make at least two monthly purchases as required by the agreement. Also, if you’re late on one payment, Discover will apply the standard-purchase annual percentage rate — currently 13.99 percent. If you’re late twice, the APR goes to 19.99 percent.

• Bank One deal: Zero percent for purchases and for balance transfers for the first 12 billing cycles after you open an account.

Catch: If you are late once during the first 12 bills, your APR will jump to 8.99 percent on purchases. If you are late twice in any six-month period, the rate goes to 19.99 percent.

• American Express deal: 3.9 percent APR for balance transfers and for the life of a loan.

Catch: American Express periodically checks your credit history. If it deems that you are less creditworthy than when it first gave you the card, you could lose the rate.

• Citibank deal: Zero percent APR on balance transfers for six months.

Catch: If you have a late payment on any card account with Citibank, your rate on all balances could go to 27.99 percent.