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?
Aside from sports betting, which obviously is the most reliable since it allows one to make use of their skills, for casino games I think my safest would be "spin match." I haven't seen it in any casino aside from one local casino that I usually make use of and this is the reason why that casino is my most used, unless I want to bet on a sport match...
I have been able to win 10x easily on that game more times than I have won in any other casino game. One thing I like about the game is that with proper calculation and some luck you should be able to win decent amount of money but the disadvantage with this game is the maximum odds that you can win; the highest you can win is 54x and nothing more than that, unlike in other casino games where the odds goes higher than 100.