Some illegal bookies will take the 10% from the losing side of the bet. So that if you bet $100 and lose, you would owe $110 and if you bet $100 and won, you would be credited $100 to your account. This difference is mostly because with legal gambling, you have to place the money up front before the bet is placed.
In an illegal bookie operation, credit is usually extended to the bettor and they can place bets while being expected to either pay-up or collect on a settle-up day after the game bet on has been played. This is all part of the house edge and can be frustrating and confusing. So that there are no surprises, you need to ask the house or the bookie what juice system they use. One must calculate the juice on any bet where you pick one side or the other.
As of this writing there are three ways to sports gamble if you live in the United States. The three ways are legal, sort of legal, and definitely illegal. It’s the illegal side of sports gambling that the police, authorities and some of society have the big problem with. The illegal sports bookie has been around longer than legal gambling and operates under a different culture.