The Big Mac is turning 50, and McDonald's plans to celebrate in a major way. The chain will be handing out limited edition "Mac Coins" on Thursday with the purchase of a Big Mac.
More than six billion coins will be handed out worldwide. Starting Aug. 3, customers can cash in the currency for a free Big Mac.
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The coins will be handed out on a first-come first served basis. The deal runs through the rest of 2018.
There are five collectible designs, one for each decade of the burger's existence.
More than a billion Big Macs were sold last year alone.