Registration bonuses tend to come in two varieties. A few websites offer free no deposit money to all new players. This means that you do not have to deposit any of your own cash and the site will give you a certain amount of money or a number of tickets to try the site out. You usually only receive a small amount and you may find it difficult to reach a point where you can withdraw any winnings.
The more common type of registration bonus is the deposit match bonus. With these bonuses, you receive an amount of money in your account dependent on how much you deposit. Most websites offer 100% and a few offer 200% of your initial deposit and most are capped but these can provide a great way to make the most of your first deposit.