I made £294 in my first month (April) after signing up to Oddsmonkey. Very intuitive and easy to follow tutorials, however word of warning; make sure you have a decent amount of capital to start off with to be able to lay your bets enough to get decent returns. I spent over £500 in my first weekend of matched betting. I obviously got it all back a few days later, but take into account the time it takes to withdraw winnings from the various betting sites and exchanges (something I didn't consider, leaving me penniless for a couple of days haha!).
Now that I've gone through most of the sign up offers, I'm in a bit of a limbo state. The easy money is over, now it's time to do some real studying