It's fairly easy really. Once the US dollar reached a value in the minus column, asking how to sort bill denominations is like asking a person to divide another number by 0. I bought a Parker Brothers Monopoly™ game the other day. I added it up and figured out that, considering the price of the board game, Monopoly™ money has recently surpassed the US dollar in value.

They've started making Duraflame™ fireplace logs out of compressed $100 bills.