One of the biggest advantages to online gambling is the wide availability of bonuses that online casinos offer. Some casinos give you money right off the bat for you to test out their games. Others require you to make a deposit in order to receive a bonus, which is either a percentage of your deposit added to your account, or a fixed amount received for an exact deposit of X dollars.
For example, Casino A might give you $10 free just for downloading, and $40 additional when you make your first deposit of $100 within seventy-two hours.
Casino B may offer you a bonus of 25% of the amount you deposit up to a certain limit.
The reason that online casinos can offer bonuses like this is simply because they have a much lower overhead cost. Less staff, less equipment, no construction required, etc. And on top of that, they make you wager your deposit (and usually your bonus) at least three times over before you can collect your winnings.
It is very important that you read the terms and conditions which are either posted on the web site or included in your email offer—how many times you must wager the deposit and the bonus, the validity period of the bonus offer, and which games you can or cannot play in order to ensure your winnings are valid.