Is it bonus rules or bonus wagering requirements? At some casinos it's the first, others use the second description. In fact there is no difference, the terms are interchangeable.
Play-through, rollover and/or wagering requirement means that when you accept bonus monies from a casino you have to agree to make the stipulated bets or wagers, otherwise you won't be allowed to cash out your winnings.
Casino owners aren't stupid, they don't want you to quit with a net win on top of having had a good time with the free money they gave you.
You will discover bonus rules vary greatly from one to the other. Some casinos have more liberal rules, others are tight and stringent. The nice thing is, you don't have to accept the bonus, if you don't like the stipulations. Always, always read the Terms and Conditions carefully before accepting any kind of bonus.
An example of a typical deposit/bonus transaction: You're new at an online casino and make a first deposit of $100, the casino gives you a 200% match bonus, or $200 free. Now you have a starting bankroll of $300. Wonderful!
BUT there is a 30 times play-through requirement on the combined total. This means you have to bet 300 x 30 = $9,000. Supposing you bet $9 per spin on a video slot machine, you'd need to play 1,000 spins, hoping that by recycling your wins you can last that long.
At most casinos bonus rules apply to both, deposit and bonus amounts combined. Some (mainly Microgaming) casinos apply the wagering requirement only to the bonus portion, not to the deposit, which is a more favorable deal.
For instance, at All Slot Casino you can get a 100% match first deposit bonus of up to $200. The bonus has to be wagered 30 times, but the deposit only once!
This means if you deposit $200, you need only wager $6,200. 30 times deposit and bonus would have been $12,000! It pays to consider bonus only wagering rules.
If playing slots is not your passion, there are other considerations. Many games are not eligible for fulfilling bonus rules requirements. Or if they are, you don't get 100% credit for playing them.
One casino's terms state "30x deposit and bonus on slots, 40x deposit and bonus on Video Poker, 50x deposit and bonus for multi-hand video poker and 60x deposit and bonus for Blackjack and Roulette." Baccarat, Craps and other games are not allowed at all.
Don't let "50 times play through for multi-hand video poker" deter you. Supposing you put up $100 of your own money and the casino gave you $200. Now you need to wager 50 times $300, that's a total bonus play-through requirement of $15,000.
On a 10-hand $1 video poker game, every 10 hands dealt costs a $50 wager. $15,000 divided by 50 means 300 bets. Unless Lady Luck abandons you totally, in 300 bets - equaling 3,000 individual hands - you're bound to have a bunch of wins that should allow you to play 300 times.
Finally, be aware that online casino owners or managers frown on players they identify as "bonus abusers", those who just barely meet the bonus rules requirements, then cash out their winnings and never come back to play again.
As a matter of fact, some casino's terms and conditions actually state that if, in their opinion, they suspect abuse, they have the right not to honor withdrawal requests.
To be sure you'll not be suspected of bonus abuse, it's best to give the casino "a fair shake". If you're going to gamble anyway, increase your play-through requirement by up to 50% before requesting a withdrawal.
The casino will consider you a valued customer and you'll be welcomed with open arms the next time you visit.