How much do you spend on gambling per month on average? I spend about $20-30 on average. But I spend it mainly on slots. Thanks to the community, poker brings profit, so $20-30 is an amount I can afford.
I think $20 is enough for me. So I set that as my limit. I also rotate the rooms where I deposit, usually $10. This way, I never deposit in the same room two months in a row. However, I don't gamble. I only play poker with my own money.
I normally don't gamble except when I sometimes have the urge to play some blackjack. Between winning and losing sessions, I think I'm about even or down a bit, but nothing alarming because I only bet 50 cents. I'm talking about online, I haven't gambled in a live casino for years.
I think for me, gambling is essentially only playing roulette after poker sessions. I wager less than 40€ on average, so the -EV is a little less than 1€. So I'd say, about 5€ per week. That seems about the right amount, pretty cheap hobby.