Crisp new $1 bills make for a long circulation future!

When possible I prefer to stamp crisp $1 bills rather than old dirty ones, since these have a higher circulation future, thus maximizing awareness of BillStamp.com's cause.

They almost don't feel like money. Money is dirty, rumpled, etc. Here's the dirtiest I've found so far:

And the crisp new ones stick together like cards in a brand new deck. But still, I wish I knew a way to get a constant stream of new ones, like directly printed from the Bureau of Engraving and Printing or something. Anyone know where you can order them?