I would most likely put it in some low IQ gambling game, like slots, dice, crash, etc. I hate those games, but would bet 1 USD on them.
I don't think that it's possible to play with 1 USD on a poker table(excluding the freeroll tournaments). Maybe blackjack is another option, where I would bet 1 USD per day. Lottery is a waste of money, but 1 USD is close to nothing. Maybe I could play a lottery game with 1 USD tickets. The national lottery in my country doesn't have 1 dollar tickets. I actually don't know about any lottery, that has one dollar tickets.