A match bonus is exactly as it sounds; it is a bonus that is awarded to players according to the amount that they have bet. In other words it is a match up to the amount of money that a player has deposited.
A match bonus can be for new players or existing players whose account at a particular casino has not been active for some time. The match up bonus is often quoted as being something along the lines of $888 match up bonus for first 8 deposits. Which sounds great when you first read it but when you actually read the small print you will realize that for every deposit you make you can get a match up bonus from the casino of $111. This is only an example and not taken from any particular casino.
It is always a good idea to really read and understand the match up bonuses that each casino offers because it may be very beneficial to you for the first few bonuses but after that it becomes less attractive. Or, it could work the other way around, the bonus payouts could get better the more that you deposit. Make sure which ever you choose that your bankroll is large enough or divided up in the right way so you can gain maximum benefit from the match up bonus.
Often the match up bonus will be quoted in percentage terms which can often mislead or distract you from what it really is. For example, a 50% match up bonus for the first 5 deposits of up to $500 really means that you only get $50 back per deposit, where as a 50% match up on all deposits for 6 months is much more beneficial as it does not have limitations. Aging these are imaginary examples of different kinds of deposits that could be and ones you should look out. As with any contract, always read the small print and know what you are going into with both feet and not just half understanding what it entails. If you go into a deal with your eyes open and all the facts in your hands, you stand to benefit from the deal and match up bonus in addition to enjoying the game much more. The best match up bonuses are most definitely the ones which offer the most over the longest time period with the least amount of conditions.