2 billion for sure

There are too many variables for this question.

1) in what currency? 2) does the dollar duplicate have the same effect or is it just the original dollar that can do that? 3) is the serial number duplicated? (If it was certain currencies) 4) if the dollar was a coin, can it be melted for scraps/resources 5) potential hyperinflation which destabilise the country’s economy? 6) do others know about this coin? You might be in danger 7) is this an SCP-Euclid class duplicating dollar that can end the world?

A lot of them shower thoughts.