Not much is more attractive to an online gambler than free money and casinos get that and this is why they offer it. Online casinos want to attract as many new players as they can get. Offering tempting bonuses can reward players with thousands of extra coins. However, getting these coins requires you to play for them first, hence the playthrough.
A casino bonus playthrough is pretty much the wagering requirements, when once met allow you to receive bonuses the casino is offering, on top of your deposit. While each casino may have different requirements, the concept is the same. There is minimum wagering requirements in place before you can cash out. This protects the casino from offering you a cash bonus and you withdrawing it without playing at all. Players are very welcome to grab these bonuses after they fulfill the necessary playthrough requirements.
If you become a member of an online casino and sign up to claim the welcome bonus the process begins and a portion of that bonus will be rewarded upon the first deposit. Then, there will be a remaining portion of the bonus that will be dispersed over a set number of subsequent deposits and games played. Players have to redeem a bonus code during their first casino credit deposit. Once these terms are fulfilled the next promotion code can be used. The more active you are with betting in games, the more you will earn with bonuses.