The national currency of Panama is the American Dollar. Officially Panama has their own currency which is called the Balboa, however it has exactly the same bill and people use both terms.
You can shop with American Dollars
Visitors with American Dollars for that reason do not have to change their currency to shop in Panama.
Visitors to Panama that do not carry the American Dollar with them can exchange their currency at one of the local exchange rate offices in or outside the malls. Interesting fact: the Balboa replaced the Colombian peso after Panama became independent in 1903.