Many parents worry about skyrocketing college costs. Starting a college fund when our kids are babies sounds wonderful, but in reality, raising a family is expensive and not everyone can start saving right away. Luckily, if finances are tight (or even if they’re not) there’s a way to save for college right now without it costing you an extra cent.

The free online service Upromise lets thousands of companies, such as Kimberly-Clark, McDonalds, Toys "R" Us and AT&T, rebate part of your spending as college savings. You can save while shopping for diapers, purchasing a new car or even buying a new home. The savings are held in custody in a secure Upromise account and can be transferred to a federally tax-free 529 college savings plan run by Fidelity or Solomon Smith Barney.

It’s simple to open a Upromise account, with no change in the way you shop and no membership card. You just enroll your credit cards and loyalty cards, and when you make purchases from a listed company, a contribution is added to your child’s account. You can divide up savings among two or more children, and friends and relatives can contribute to your savings.

“Families can get the most use out of Upromise by inviting their family and friends to sign up," says Jim Doyle, Upromise spokesperson. "A grandparent that can’t afford to write a check for tuition can help their grandchild by shopping for groceries and gas and linking savings to a grandchild’s account.”

The companies that have teamed up with Upromise hope to foster customer loyalty by paying the rebates and an administrative fee. “Upromise adds a whole new dimension to the relationship of a company to customer,” says Doyle. "Will you buy a car you don’t need because of Upromise? No. But will you go to a GM car dealer when you know the purchase will benefit your child? Absolutely.”

The savings from rebates can add up; however, don’t rely on this account to pay your whole college bill. Upromise estimates that a member with a total household income of $70,000 and a newborn child could save $10,029, but according to Collegeboard.com, the current cost for in-state public college is $11,976 and private college is $26,070.

To help parents grow their accounts, Upromise plans to add more companies offering rebates along with a new “gifting” feature. “We’re expanding into gifting so that friends and family can give the gift of college instead of cash that may disappear into an arcade,” says Doyle. This feature will work like a gift certificate from a retail store, allowing monetary gifts to deposit directly into a 529 plan.

Want to see more?

• Finding Funds: A Guide to College Scholarships
• Achieving Your College Savings Goals: Understanding the Keys to Success
• Financing College: Where to Put Those Heard-Earned Bucks
• Talk about it!