Sometimes they do. I find after about 2 months of inactivity with them they'll throw a £10 pound free bet your way. Once all the sign up offers have dried up (which I made about £700 from inc cash back etc), I've found I'm dribbling in about £40 a month after that.
I stay away from the complicated acculmulator style free bets - way to easy to make a mistake and not qualify for the free bet - although they do offer massive returns if you do it correctly.
Cool, are there any particular ones?
I don't want to open too many accounts while I'm starting out, just keep it simple for now