It's easy to rack up points on a variety of purchases with these three cards. By Lisa Gerstner, Contributing Editor From Kiplinger's Personal Finance, July 2013 You can make a variety of purchases with these cards and reap a sizable rebate. You’ll earn 3% or 5% back in their top gas or retail categories, at least 2% in the second earnings tier, and 1% on other purchases.BEST REWARDS CARDS BY CATEGORY: Cash-Back | Travel | Gas/Retail | Airline PenFed Platinum Rewards Visa www.penfed.org Interest rate: 9.99% through June 30, 2014 Annual fee: None Advertisement Typical annual rebate: 38,634 points You’ll receive five points per dollar spent on gas, plus three points per dollar for grocery-store purchases and one point per dollar on all other purchases. Redeem your points for travel, merchandise, gift cards or prepaid cards. A $50 retailer gift card or PenFed Prepaid Visa Reward Card requires 5,000 points. TrueEarnings Card From Costco and American Express www.americanexpress.com Interest rate: 0% for six months, then 15.24% Advertisement Annual fee: None with a Costco membership (starting at $55 a year) Typical annual rebate: $295 Available only to Costco members, this card pays 3% on up to $4,000 annually in purchases at gas stations (1% thereafter), including Costco gas stations (many cards don’t offer top rewards for purchases at warehouse-store gas stations). You’ll also earn 2% for restaurants and travel and 1% on other purchases. Earnings arrive each February as a Reward Coupon, which you can exchange for cash or merchandise at Costco (you must redeem it by August 31 of the year in which you receive it). Amazon.com Rewards Visa from Chase www.amazon.com/rewards Advertisement Interest rate: 14.24% to 22.24% Annual fee: None Sign-up bonus: $50 Amazon gift card Typical annual rebate: 26,834 points Advertisement Frequent Amazon.com shoppers will do well with this card, earning three points per dollar for spending on the site. The return on other spending is decent, too: two points per dollar at gas stations, restaurants, office-supply stores and drugstores, and one point for other purchases. One hundred points are worth $1, and you can use them to make partial or full payments on Amazon purchases (you can also use points you’ve earned with other eligible Chase credit cards, including Sapphire, to make purchases at Amazon.com). Or redeem points for cash back, gift cards and travel through Chase Ultimate Rewards.