I once offered a sales team an incentive that, yes cost less than 3 bucks. I bought 9 candy bars at a local grocery store (on sale, 3 for 99 cents). For 3 hours during a peak sales period anytime someone sold a specific “up sell” item was rewarded with a candy bar.
Competition was fierce, everyone had there favorite candy bar picked out and wanted to get it before someone else did.
I ran out before the time was up and everyone was happy. Especially me, I had nine more sales. Total investment $2.97. It was a great spur of the moment boost and everyone had fun.