They do the same thing as other sports bookmakers do. The odds aren't based on how big the team is favored over another team they are based on what point spread or points for the over under are needed to try to get approx. half the players betting to bet on either side of the line. If Chelsea is playing Manchester City the oddsmakers know that every one would bet on chelsea to win thats why they make Chelsea favored by say 2 goals that way the better has to decide if they will win by atleast 2 or not then you will get more people betting on Manchester City cause even though they are not near as good it is still hard for a soccer team to win by 3 goals in order for you to win a bet on Chelsea. Payouts are determined by the odds. If you do pick the Point Spread you will usually make about 91% of your bet because the oddsmaker takes a % for his commission or juice. Usually for every 10 bet on the point spread you will win 9.09 so you will get 19.09 back on a 10 bet. the money line is based on how big the difference is in the teams on the point spread it it is to big they wont even have a money line because they dont want o give away money on say Ohio St. vs Bethune Cookman. They know as well as you do that Ohio St. is going to win so they dont put money line on the game they make you decide if Ohio St. is going to win by 35 or not.