How do free spins actually work in gambling?

[Alphakilo]

The whole free spins and 35x wager is really strange, assuming I am in this situation, the casino expects me to meet up with the 35x wager? Let’s not forget winning is never guarantee, while many will submit to the idea all because of gaining access to withdraw free spins certainly they might lose everything during the process.
Setting 35x wager before withdrawal no longer seems as a free offer, well being able to win free spins comes with requirements, fair enough the casino also wants something in return but 35x wager is actually discouraging.

35x is the most common number in most of the casinos, and since it is free money with huge risk the players can always decide to ignore the bonus and continue to gamble with no strings attached but most of them will be eager to complete the requirement and wants to claim that free money.

I see free spins as a controlled market for the casino platform. To verify you as the player, to keep you playing and to keep your withdrawal low.
So free spins is just entertainment not for profit and a negative expectation games which is not an investment but merely for just the fun of gambling so far.

[famososMuertos]

Today, it depends on the specific factors involved with Free Spins. Generally, they should live up to their name, meaning they're free, but the reality is that sometimes they aren't truly free. They can be received through various promotions, but some require conditions, the most common being a prize limit. This means that if you win a large prize, it's capped at a certain amount.

Wage requirements are very rare when a high rollover is imposed. In fact, the norm is to take your winnings and withdraw them or place unconditional bets. Any casino that offers free spins, except for those for deposits that are part of a bonus, will likely have some kind of condition.

[Smack That Ace]

But I created an account at a casino yesterday, and there were free spins, and each spin was probably 20cents and I won like $53 there but from what I understand from their rules and regulations, I have to deposit $17 and wager 35x or maybe more than this to withdraw $53. I actually have very few  free spin type welcome bonuses so I can only give one example for now. 

Lol, if you have to meet 35x wagering requirement just to withdraw your own winning and on top of that, you're required to make deposit, how can this possibly be called free? It's ridiculous.

If deposit is mandatory to make withdrawal, then it is effectively deposit based bonus, merely marketed under the name free spin. Your actual mistake here was not reading terms and condition before signing up for those so called free spin.

But you got that lesson cheaply.

So, don't rush now, thinking, I've won, let me make deposit and withdraw my winning.
If by some stroke of luck you manage to meet all their requirement, you will find that they keep you hanging by citing KYC, AML or bonus abuse as excuses.
Most probably these are scam casino. If their intention were good, they wouldn't impose such high wagering requirement.

[Findingnemo]

The whole free spins and 35x wager is really strange, assuming I am in this situation, the casino expects me to meet up with the 35x wager? Let’s not forget winning is never guarantee, while many will submit to the idea all because of gaining access to withdraw free spins certainly they might lose everything during the process.
Setting 35x wager before withdrawal no longer seems as a free offer, well being able to win free spins comes with requirements, fair enough the casino also wants something in return but 35x wager is actually discouraging.

35x is the most common number in most of the casinos, and since it is free money with huge risk the players can always decide to ignore the bonus and continue to gamble with no strings attached but most of them will be eager to complete the requirement and wants to claim that free money.

I see free spins as a controlled market for the casino platform. To verify you as the player, to keep you playing and to keep your withdrawal low.
So free spins is just entertainment not for profit and a negative expectation games which is not an investment but merely for just the fun of gambling so far.

If it was meant for fun then the players already have demo mode with no risk of losing their money, free spins are kind of an activity to keep the player engaged and also an advertisement to try the game because some player only associate themselves with few games but casino wants to to explore more games.