I get asked that question a lot these days. I'm never quite sure what the answer is. Before we had the US mints scattered across the country, we had lots of different places that issued their own coinage and paper money. (Think Confedrate money and you'll get the idea.) You might have been able to use a priavte firm's issued coins or paper around your neck of the woods, but outside that perimeter, no one else would honor it. But now, those coins are collectable and worth more than the face value. However, you can't buy groceries or gas with them. So invest if you like, collect if you can and check out this coin that really makes my point.