Odds exchanges are sites where gamblers play against each other. Odds exchanges get the matches and handle the money, correct and pay out. For this they get a commission on the winnings, usually 5 %. This means that in reality the odds are lower, on odds 2,5 % goes from the winnings so the odds are in reality 1,95. To calculate odds, Click Here.
Despite this the odds exchanges I suggest often have high odds. But above all we must have odds exchanges so that by using risk free bets (sure bets) by moving winnings from bookmakers by losing at the bookmaker and winning with a contra bet on the odds exchange on the opposite, which is explained on own side.
This is much more difficult than winning. Winning is very simple, which is done on the first bet. But you must not make a mistake; the whole learning curve is not to make mistakes, not to learn to tip correctly. To win you do not have to know anything about sport.
Betfair. You will need to take on Betfair, 5 % commission, a difficult site, customer unfriendly policy. Be prepared to experience bad treatment where the standard answer is "it is not our policy", "hang on for a bit" or "do it yourself".
But Betfair is biggest, have the most players and most capital so you will probably find you will need them. Be prepared so you can tolerate them.
You will get fast correction and can often play again with the same money the same day; there are often large sums to play and several events. Betfair were the first and invented the odds exchange. If they had only looked after their customers - like Betsson does - they would have had a monopoly.