"Alf's back....in POG form!"...Millhouse, The Simpsons
The pog was a craze started back in the 90's with these cardboard disks kids collected to presumably play some type of game where they attempted to gain pogs from other players. Like most fads it came and went quickly but the use of them by the Army Air Force Exchange Service (AAFES) continues to this day (to the best of my knowledge, if they have discontinued this practice please let me know in the comments) for the use in on base commerce. When you would go to the PX and buy something with cash any change due you would be returned with one of these cardboard pogs. They have the denomination the pog represents on one side and a picture on the other. The idea was that the transportation of heavy bags of coins overseas would outweigh the actual cost of the coins themselves, so these were put in play to give troops something to use in lieu of coins in theater. Once out of theater any remaining pogs could be used stateside or converted to cash at AAFES. I, like some other folks, just threw them in a box when I got back to my hootch for the most part and brought them home as a souvenir.
Eagle Cash card
They tried to get rid of all cash transactions by also using an Eagle Cash card overseas, which is basically a pre-paid debit card that you tie into your bank account that is accepted by AAFES and other vendors on base. You transfer funds to the card from your account on a terminal, and then use the card like you would a debit card in place of cash otherwise. If you lose it overseas you don't need to worry about someone on the other side of the globe from your (normal) home having your credit card number. We were cautioned never to put large amounts of cash on it, just what we would need for a few days at a time.