Recently I decided to give out gift cards as high hand jackpots for a 1 table NL game. We played from 7pm to 12pm so I did one high hand per hour. The gift cards were various Starbucks, In-N-Out, Burger King, etc gift cards, mostly worth between $10-$25. Turned out to be a hit with the players!
My rules were that any high hand that was full-house or better qualified. I kept track on my phone during the game. If we were in a hand when my hour alarm went off that hand would qualify for the previous hour. If a player showed their hand after everyone folded (before the river) that hand would qualify.
If no one got a high-hand in an hour period then that prize would roll over to the next hour (offering 2 prizes). Luckily someone won every hour, and as it turned out 5 different people won, so the joy was spread throughout the table lol.