Price paid currency selcetion

When entering the price paid for a unit, add an option to select which currency this price is for. When toggling between the display currency on the main website, the price paid would change to the displayed currency.

Example: I buy a game in Japan for 1000 yen. I could put 1000 yen into the "price you paid" section. When I return to my collection, the price will display in USD if USD is selected as the current display currency.