You can lost everything if you gamble with a lot of money on risky gambles. The best way to gamble on sports is to put a lot of tickets with not much money.
And as the question is asking, how much you can lose with gambling? We know that it's given anyone can lose all he got.
But for me, I can only make it up to 0.01
BTC I'm not that a severe gambler and that's the only amount I'm willing to lose.