Eventually this thread will recommend every game in the casino.
I vote blackjack. Generally the house edge if you play well is only on the order of 2-5%, so you won’t lose much over the long term.
The biggest mistake people make is trying to gamble with a low limit like $50 or something. You lose 3 or 4 hands in a row, which will happen, and you’re broke. Whereas if you are playing with a $250 bankroll you can weather a few losses in a row.