In basic terms, a sign up bonus is a form of reward given by an online sportsbook or casino operator that provides players with a certain amount of free bets or free money to use on the online website or mobile app of that operator. There are 2 primary forms of sign-up bonuses, including that of deposit bonuses and free bets. A sign-up offer is usually given to a new player that has just registered with the site and made their first deposit of a specified amount.