Usually for me it's around 0.1. I start a game with 0.01 in my favorite game (progressive slots of 5, with max lines on). I do a couple of spins, and at least one of them will put me into a decent game where I start making a decent amount of gains, but eventually I get too greedy and lose it all.
So once I get past 0.1 invested in gambling, I don't gamble again for an entire month, sometimes more.
What is your limit then??
The best way is to start small, like $10-$25 on an account. You will only win long term if you are directly against other players like in poker, even then you have to beat the house edge (rake) before making a profit. If you are playing games because they are all flashy or make the right noises, it means the host will win all your money. It all requires statistic analysis if you want to make profit, unless you are the very best you'll mostly be bleeding money.