If you’re not already signed up to Quidco, I’d definitely recommend it. I’ve received over £700 of cashback over the last three years. The biggest cashback payments have been for switching gas and electricity providers. There are quite a few of these cashback sites around, but Quidco seems to be one of the better ones as far as I can tell.
The idea is that if you want to buy something from, say, play.com, instead of going straight to play.com you go to quidco.com first. If they have that site on quidco you click on their link instead, which takes you to play.com but records the fact that you went there via quidco. Then when you make a purchase from play.com, quidco gets informed and you get either a fixed amount of cashback or a percentage of your purchase back.
Each year Quidco take the first £5 of your earnings as a subscription fee, although if you don’t make £5 (which is quite unlikely) they don’t take anything.
I should also mention that if you sign up using this link and make £5, I’ll get a extra £2.50 bonus, so I do have an ulterior motive to getting you to sign up!