Answer:
An old coin, winning lottery ticket, or an old dollar.
Step-by-step explanation:
It seems that the objects setting is in a wallet because it has a receipt, George Washington's ugly green face(a dollar), and I believe the " lackluster billfold" the narrator speaks of is part of a wallet. The object saying it is worth so much money, but is stuffed into a wallet and forgotten about leads me to infer that it could be an old and rather valuable form of currency that blends in, making the person "truly forget about me". Another option is a lottery ticket, the winning one too if its worth so much money, and people often put them into wallets and such and forget about them. These things lead me to conclude that the object is either an old coin, winning lottery ticket, or an old dollar.