Lamarr and Anthiel received a patent in 1941, but the enormous significance of their invention was not realized until decades later. It was first implemented on naval ships during the Cuban Missile Crisis and subsequently emerged in numerous military applications.
Cash back credit card reward programs started out rather simply, offering a flat percentage rate (typically 1 percent of purchases) rebated back to the customer in the form of a check at the end of the year or a statement credit.
Lots of credit cards give you cash back rewards, but you can double your rewards with a simple trick: just combine it with a cash back checking account. Charge everything to your cash back credit card, then pay it off with the checking account and you'll get (nearly) double the rewards.