There is **no separate currency for Wisconsin**. The currency used in Wisconsin is the **United States Dollar (USD, $)**, the legal tender of the United States of America. Wisconsin has been a state since 1848 and has never issued its own currency.
Pre-Civil War, some Wisconsin *banks* issued private banknotes (obsolete currency). These are collectibles, not legal tender. During the Civil War, US National Banking Acts standardized currency.
Bottom line: In Wisconsin, as in all 50 states, **the currency is the US Dollar**.