There are a couple of cards that offer cash back to members of the military and their immediate families. The USAA Cashback Rewards Plus American Express Card combines the prime customer service of American Express with the support of USAA. With this card, you get 5% cash back on gas and purchases at military bases. You may also earn 2% cash back on groceries, and 1% cash back on all other eligible purchases. The high cash back rate, plus no annual fee may make this a strong contender for your primary credit card.