How much money should I set aside before playing?

Decide the amount before you open the site, and make it money whose total loss changes nothing in your month. Set it as a fixed deposit ceiling per week or month using the operator's own deposit limit tool, so the decision is enforced rather than merely remembered. Size stakes against that figure: a EUR 200 bankroll at EUR 0.50 a spin buys around 400 spins, at EUR 5 a spin around 40. Set a session clock alongside the session budget and stop at whichever comes first. Never redeposit to recover a loss. None of this improves your odds; it only bounds the damage.