Gie it to charity, I dont know if you’re a believer but you will get reward and the person lost the money will get reward also, they may never know in this lifetime who they helped but they will find out in the next, it would be a great gift from you.
A couple of years ago I had found $60.00 still in the ATM machine.
I asked around, but no one knew anything - so I went and gave it to a group selling hot dogs/collecting money for Charity.
They did not have receipt book and promised to send me a receipt for it, despite my ringing up a couple of times - I never got the receipt.
This time I’ll make I’ll make sure it’s a genuine charity.
buy yourself some nice personal hygiene products - it counts as charity towards those that come in contact with you, and you are getting yourself a little something.