See more of the story

Buried in your billfold, bound in a money clip or stuffed in a pocket on your phone case are untapped benefits on credit and debit cards that could save you hundreds of dollars a year. Here are five money hacks hiding in plain sight.

1. Use a roundup app. Build savings even as you spend money by linking your credit and debit cards to an app like Acorns or Digit. These apps automatically round up your purchases to the nearest dollar and then add the difference to a savings or investment account.

2. Maximize your card benefits. Credit cards often come with valuable but easy-to-overlook benefits. Among them: Travel perks, including airline cards that offer free checked bags and airport lounge access.

3. Cellphone insurance. Wells Fargo, U.S. Bank, Mastercard and other credit card companies offer cellphone coverage with certain cards when you pay your bill with the card. Automatic credits that reimburse you for things like travel expenses, ride-shares, meal delivery or purchases at select merchants, up to a monthly or annual limit. Read your credit card's benefits guide to see what's included.

4. Use your rewards cards for everything. Every purchase that isn't on a rewards card is money left on the table. Rewards cards essentially give you a discount on all your spending. Depending on the card, how its rewards are structured and where you use it, you will typically earn rewards equal to 1% to 6% of the purchase price.

5. Stack savings with a cash-back portal. Websites such as Rakuten (formerly Ebates) and BeFrugal pay you a percentage back on every qualified purchase from participating retailers. A Rakuten spokesperson, for example, said the average member earns 4 to 6% in cash back on purchases made through the site, which can add up to hundreds of dollars a year.

The trick is to get into the habit of checking the sites before you shop.

6. Know your price protections. Another good reason to keep your receipts: You might be able to get money back if something you bought goes on sale for less somewhere else. If your credit card has price protection, you can claim a refund of the difference if you submit proof of the lower price on an eligible item within a particular time after your purchase. Don't have price protection on your card? Several major retailers offer their own version if certain competitors offer the same item for less. Participating stores include Bed Bath & Beyond, Best Buy and Home Depot.

Robin Saks Frankel is a writer at NerdWallet. E-mail: Twitter: @robinsaks