These three cards let you earn back generous percentages on your purchases. By Lisa Gerstner, Contributing Editor From Kiplinger's Personal Finance, July 2013 Earnings from these cards have a clear dollar value, and you can use the cash rebate to buy whatever you like. Redeem your rebate with a statement credit, check or deposit into your bank account.BEST REWARDS CARDS BY CATEGORY: Cash-Back | Travel | Gas/Retail | Airline American Express Blue Cash Preferred www.americanexpress.com Interest rate: 0% for 12 months, then 12.99% to 21.99% Advertisement Annual fee: $75 Sign-up bonus: Spend $1,000 in the first three months and get $150 back Typical annual rebate: $384 The healthy 6% you will earn on supermarket purchases makes this a top-notch card. After $6,000 in supermarket spending each year, earnings on groceries drop to 1%. But if you spend at least $105 per month at the supermarket, you’ll earn back the annual fee. The card also pays 3% on purchases at gas stations and select department stores and 1% on everything else. Redeem your earnings in Reward Dollars, which can go toward statement credits, gift cards or merchandise. Advertisement U.S. Bank Cash+ Visa Signature www.usbank.com Interest rate: 13.99% to 23.99% Annual fee: None Typical annual rebate: $358 Advertisement Flexibility is key to this card’s appeal. Each quarter, you choose two spending categories for which you’ll earn 5% back; the options recently included restaurants, hotels, department stores, charities and even cell-phone bills. Then you pick one category that will earn 2% on purchases; recently the choices were gas stations, grocery stores or drugstores. All other spending earns 1%. You can redeem your cash anytime and in any amount. Send it to a checking or savings account or get statement credits. Rewards expire after three years. Capital One Cash www.capitalone.com Interest rate: 0% until May 2014, then 12.9% to 20.9% Annual fee: None Advertisement Sign-up bonus: $100 back if you spend $500 in the first three months Typical annual rebate: $300 If you prefer a straightforward cash-back card with a decent payback, this is your best bet. You’ll effectively get 1.5% back on spending: Every purchase earns 1%, with a 50% bonus on your earnings on the anniversary of opening your account. Redeem your cash at any time, or get gift cards or donate to charity with your rebate.