The two main types of casino bonuses being given to this date are the free play bonus and free casino spins. Both have their advantages and both require you wager the bonus according to the casinos rules. The free play will give users a large sum to play with the advantage of this would be opportunity to play more of the casino games where you will be hitting the bonus rounds within the games so you can view the machines a bit better.
The disadvantage to this bonus is you only have an hour total of play at most of the online casinos, which is not a whole lot of time but is enough to evaluate the games. You still will be limited on the amount you may transfer into the normal casino account and at most the places this will require a purchase to move the money. Players do enjoy this bonus as they pick and play what they want instead of just playing what the casino has picked.
Getting spins was something the casinos brought in a couple years ago and has become one of the more popular bonuses so far. The free spins are credited to one machine where you just go to that slot game and active them. Since you are just spinning without losing money you can build up a bit whether it be a 100 or several hundred. Once the spins are completed you can continue playing that game and why not if it is paying well, or you can go pick other machines to play. Some users move on to the progressives after since they have a few credits which may win them a lot of money. On the bonuses most online casinos do restrict the maximum cash out to a small amount with the exception of the jackpots that can be won on progressives. So it makes sense to play them as a potential way of coming out way ahead. This is something the users should be checking the casino support to make sure it is acceptable and if you win they will pay it out.
That the basic run down on each of these free casino bonuses and gives you a better idea on which you may want to test. You can try them all as there is no limit on how many offers you can take just a limit on only one offer per casino.