Paying for your purchases with credit cards could earn you money for a child’s college education. It even might help pay down student loans after graduation. Here’s how…

Fidelity Rewards Visa Signature card. This no-fee credit card gives you 2% cash back on all purchases, and you can have Fidelity automatically shift the money to a 529 college savings plan, which includes various mutual fund investments that you can choose plus tax-free investment growth and possible tax deductions in some states.

Those 2% rewards can add up. Example: If you spend $25,000 a year with the credit card for 20 years and the investments you select for your 529 plan earn a 7% annual return, that’s nearly $22,000 for college.

Grandparents also can take advantage of the Fidelity card for college savings, but there’s a twist. If you want to save on behalf of a grandchild, it’s best to call the number on the back of the card and ask to always have your rewards pushed directly into the Fidelity 529 account previously opened by the parents. (Grandparents can open 529 accounts, but grandparent-controlled 529 accounts receive less favorable treatment from college financial-aid offices than parent-controlled accounts.) For details, put “Visa Signature” in the Fidelity.com search box.

Register your credit cards and store loyalty cards with Upromise. This free program offered by student-loan issuer Sallie Mae enables students and their family members to earn cash for college by spending at any of the thousands of participating merchants and restaurants. You can…

Earn up to 10% back on online purchases made from hundreds of merchants. To do this, simply navigate to the online merchant’s website through a link on the Upromise site. Examples: Earn 3% cash back at Amazon.com…5% back at WalMart.com.

Earn 5% cash back on meals at more than 10,000 participating restaurants. Simply pay using a credit card that has been registered on the Upromise website.

Qualify for cash back on certain purchases at many supermarket and pharmacy chains. Earning this money takes a bit more effort—you not only have to register your store loyalty cards with Upromise, you have to activate the offers that interest you online before shopping.

Cash earned through Upromise is automatically deposited into a college savings plan, such as a 529 or Sallie Mae “Upromise GoalSaver Account.”

Alternatively, this money can be automatically transferred to a loan issuer to pay down a college loan…or you can request it in the form of a check.

You also can sign up for the Upromise MasterCard. It offers 1% cash back on most purchases and as much as 5% back on purchases made at Upromise partners—on top of the rewards program described above. (UPromise.com)