One of my geeky friends recently introduced me to Quidco, a cashback site that helps you get money back on your online purchases. It's very simple - Quidco pays you the commissions that they receives for your transactions from merchants listed on their site.
The list includes some of my popular online stores including Tesco.com, Dell, iTunes, Marks & Spencer, etc. My power company (Scottish power) and even hotels (Travelodge).
They will transfer your earnings to your PayPal or BACs account.
It is totally free to join and they just take an annual £5 subscription from your Quidco earnings (not charged).
Wish I had known about this earlier. I could have got some money back from all my online transactions.