If I was down to my last $100, I Darn well wouldn't lose it.
I found $50 in a bank envelope in front of my house once, wife put an add in paper stating name the bank and the amount to claim it. All kinds called and asked how much it was .
We ended up spending it
I think it was one of the trash haulers.
Oh, and while doing Highway cleanup with the Boy Scouts last year, three of found $20 each.