I'm not sure if they're still there or not, but there used to be $1 9/6 Jacks or Better machines at the Riviera between the slot club and where they hold the slot tournaments. The Stratospher is close to the Riviera too, and they used to have 9/6 Jacks or Better for a dollar on some of their Game Maker machines. Try the Stardust too; the bartop machines have some $1 games, and then some of the Multi Strike machines near the East Tower elevators. All of this could have changed, but those would be good places to try.