The match bonus is the most common casino bonus. The beauty is in the simplicity they say. The match bonus is a percentage match, often 100%, on you first deposit. For example, if you deposit 100 credits and the match bonus is 100%, you will get 200 credits to play with.
Just like many other types of casino bonuses the match bonus are tied to terms and conditions. This means that the casino limit your possibility to withdraw the bonus money directly. The casinos often applies wagering requirements that have to be met before any withdrawal can be made.