It's really easy - if you want to gamble without losing money - then don't gamble.
In addition to this stuff, he can also use the casino playmoney, like FJC (fortunejack's play money) or get it some satoshi form the sites faucet. There are lots of casino that gives you an opportunity to try their site even without spending a single cent. Most have either a faucet where you can claim a few satoshi and try them in Dice.
as of OP losing all his token, the decision is still up to him. If he wants to implement control, then he can minimize his loses and avoid unnecessary bets and expenses in gambling. The good thing is, he can even reagain some of his losses every session. This is one strategy, using martingale, it is best to bet with 200% multiplier, the reason is that you can gain the 1/3 of your betting amount after recovering the previous losses. This needs a good approach and control. but this will be rendered useless if greed take over. Just a couple of losing streak and a win at the end should give you enough win for the day and must stop and play the next day.
Yes, that's what I think. Very simple and easy to answer such questions. Actually if you do not want to lose money, do not take anything risky like gambling and trading. Just do something more sure and you believe. Like me who is afraid to take risks, so I never jumped into the world of trading or gambling. I just invested in Bitcoin and popular cryptocurrency. And as you said above, to reduce or eliminate losses to gambling and trading, you can collect some money from the internet by doing various online jobs. That way you will not be afraid of loss because the money you use does not come from your salary. I myself do not like gambling so I use my side-jobs to invest.