Last week the Telegraph and BitterWallet reported on research that found most Britons have never used cashback websites and as a whole are losing out on £3.3 billion each year–an average of £123 per family–as a result. What is a cashback website? And just what do you need to do to get your piece of that pie this year?

Martin Lewis of Money Saving Expert explains:

Cashback sites take advantage of the way commercial payments from one website to another work. They simply list product providers and retailers, and when you click through to these websites, they get paid for ‘providing leads’; in a similar, but not identical way to how most web-adverts usually work.

Yet with a cashback site, when you’re logged in, the revenue raised from your click is attributed to you so the site can pay you some or all of the money it receives.

Digging deeper, the Telegraph offers some specifics:

Once shoppers have done so they can shop for insurance, groceries, electricals by clicking through to the retail sites. Every purchase generates between about 4 per cent and up to 10 per cent savings, which is paid to the shopper either by cheque or directly into their bank account. A shopping spree of £300 can lead to a cheque about a month or two later of between £12 and £30, more with some retailers.

Currys offers 3 per cent cashback, Expedia travel site offers 10 per cent, Boden clothing site gives back 5 per cent and the Body Shop offers 14 per cent. In most cases the cashback is earned on all purchases.

The most popular cashback websites in the UK include:

Quidco–Free to join with a £5 annual admin fee. The site also has community features, including a blog and Quidclans, which sound cool but aren’t actually very well explained.

Cashback Kings–Free to join with no annual fee. The site guarantees you find the best deal through the site by offering a deal-matching scheme. Also has a blog.

Top CashBack–Free to join with no annual fee. Offers a “tell-a-friend” bonus and a charity-donation option. Also guarantees the highest cashback and has a blog.

The sites all seem pretty similar to me. Does anyone have any personal experiences to share in the comments?