How it worksMatched betting or bonus arbitrage is the process of taking advantage of a difference in odds between a bookmaker and a betting exchange, or where a bookmaker will offer risk free bets or bonus money for betting on an event or outcome. There are actually dozens of these offers every single day across the 100+ UK bookmakers.
A basic example is the odds of tossing a coin, they should be 2/1, so you've got a 50% chance of winning if you choose (for example) heads. Matched betting works because often a bookmaker (trying to get more business) will offer enhanced or boosted odds, so they might offer odds of 3/1 on heads. The actual odds haven't changed however, so if you place a bet at 3/1, and place the opposite bet (a lay) against heads at 2/1, you can make make a profit no matter what the outcome is.
So what is a betting exchange?A betting exchange is a special type of bookmaker which allows you to not only 'back' an outcome (e.g. Arsenal to win) but 'lay' or bet against an outcome (e.g. Arsenal not to win, which seems more likely these days). Whereas a bookmaker makes money by offering odds on an event that add up to more than 100% (their 'overround'), a betting exchange makes money by charging a small commission on each winning bet (between 2-5%).
Expected value and casino offersIn addition to sports betting, a big part of matched betting is casino offers, e.g. "deposit £10 play with £20". These offers often require you to wager your winnings a certain number of times, for example a £5 bonus might have 20x wagering requirements, so you'd have to spin/bet £100 to release the bonus. Some offers are +EV, others are not. EV or expected value is a measure of long term outcomes, i.e. if you did the same offer 100 or 1000 times, you would expect on average for this amount to be won. If the wagering requirement is too high, the offer becomes -EV and you would expect on average to lose money completing the offer, so we ignore those.
What is Oddsmonkey?To put it simply, OddsMonkey is a website that explains all of this better than I can, has a daily list of all the available offers, and exactly how best to complete them. It has dozens of guides and calculators, and a rich and active community of helpful people all doing the same thing. Their customer support is outstanding, even at 10pm at night. It's only £15 per month, which you can make back in a single day without breaking a sweat.
During the first month it's very easy to make money just by signing up to several of the bookmakers and taking advantage of their new customer offers, you should easily be able to make over £750 in the first month. In subsequent months, you can make as much as you're willing to put into it, there's a great deal of offers and techniques available that can bring in anything from £500 to several thousand each month.
The only downside is that the more bookmakers you sign up for, the more text messages, app notifications and emails you'll get every day. However on the flip side, if you didn't get the notifications you can risk missing out on a decent offer. In the long term, you are likely to get restricted by several of the bookmakers - matched betting isn't illegal, but bookmakers like making money, and if you consistently make money, then they don't.
If you're interested, you can sign up here.