Sometimes casino give no deposits and you can get lucky. You should be very lucky if there is a high wager for wagering, and sometimes there are no requirements for a wager. I was lucky 2 times, I withdrew about $ 20 from bc.game and about $ 30 from bitsarcade. In bc.game they gave a few dollars without conditions, you just had to play the minimum amount for withdrawal without a wager and withdraw the win in half an hour. At bitsarcade.com, they also gave no deposit without a wager, you just had to play the minimum amount for withdrawal. But there were already some problems, at first the forum thought that they did not pay and the project was scam. But as it turned out, the casino pays and operates as usual casinos, everything is fair. How much have you withdrawn from no deposit, maybe someone won the jackpot playing for no deposit?
Well, there are casinos that won't even allow you to withdraw a cent before you deposit. I had a similar bad experience at TrustDice earlier, when I was tipped by a chatter and managed to roll it nicely to a decent amount to withdraw. Once I tried to withdraw, I was told that you cannot withdraw unless you have at least deposit some money and rolled it over 1x minimum.
Then there are casinos like stake with instant withdrawals and I don't think there are any such weird limits or anything. Personally, I have been lucky with some sites when I got free spins and sometimes free bets but nothing big enough to show off.