Almost all sport books will give you a bonus when you first start placing bets with them. A couple of common types of bonuses are:
The free or risk free bet.
The risk free or free bet is most likely the most common type of odds bonus that sport books offer. This types of bonus give you your money back if you loose on your first bet. This is why it is called a risk free bet. There is no risk when you place your first bet. Either you win or you loose and get your money back.
It is common that you need to place your first bet the same day as you first deposit money to get a risk free bet. It is also common that your first bet must meet certain odds requirements for you bet to be risk free. This odds requirement can vary between different sites but it is usually 1.80.
Always read the complete rules before you place a risk free bet. IfF you do not you might place a bet that does not fulfill the terms that needs to be met and you end up not only loosing the money you bet when you placed what you thought was a risk free bet put also the opportunity to place a risk free bet.
The risk free bet must be the first bet you place. If you place a bet that does not meet the criteria for a risk free bet you loose your chance to place a risk free bet. You can usually not save the risk free bet until you need it.
A profitable but frowned upon way to make money with risk free bets is to bet on a game that only has two possible outcomes and bet on both outcomes using risk free bets in different sites. This way you can leverage risk free bets on a number of different sites into one big payday at one of them. The more sites you start with on level one the more profit you will end up with at the end
Regular cash bonus
The second common type of bonus is the welcome bonus where you get a percentage of you first deposit as your bonus. You might as an example get 100% up to 100$ as a bonus. This means that you can get a maximum off 100$ in bonus and that you need to deposit 100$ to get it. If you deposit 100$ you end up with 200$ to bet with.
The bonus will need to be turned over a certain amount of times before you can withdraw the money.
This type of bonus have many benefits compared to the risk free bet. The risk free bet only affect one single bet, a bet that needs to be placed with a certain odds, and forces you to bet big if you want to maximize the value of your bet.
When you get a cash bonus you can choose to spread it over a large number of smaller bets and are not forced to make a bet the first day. Since you can use the bonus to place a large number of smaller bets you can get a lot more excitement from this bonus than you can from one single free bet.
Always make sure that you read the full terms and condition before you accept a cash bonus. That way you know what is required of you and when you are allowed to withdraw your winnings. If you try to withdraw your winnings before meeting the bonus terms your account might get suspended.