Personally if I want to turn a small amount into a quick x profit for fun I do,
10$ into 5-10x I see the most success I have with games like Mines.
I try avoid slot games with low budget, what is your "safest" game for you that you feel lucky on, and have most fun with?
Dice or limbo. They're all 3 the same thing if you know anything about casino originals, the animation is the only thing different. I personally have had the most success on dice type games though if I need a boost.
You might also try to get lucky on a table game, IMO a bigger risk but a run can happen on a lucky shoe or a hand of blackjack.