Military payment certificates were issued in lieu of cash to American troops stationed in certain foreign countries. They were issued from just after the end of World War II to just after the end of the Vietnam War.
The military issued these payments in certain markets where troops were able to make a profit from currency arbitrage when paid in conventional dollars. MPCs were only valid within certain zones and could be converted to regular currency when leaving those zones. MPCs had a colorful design similar to that of some bank notes and were issued in denominations ranging from 25 cents to $20.