As a nation, we spent around £965m a week shopping online in August 2016, nearly 20% more compared with the same period last year.

And with online sales booming, savvy Brits are finding creative ways to grow the pound in their pocket. One popular method is cashback sites.

Here, we explain what cashback sites are and three users share their experiences, including one Londoner who has made more than £850 this year alone.

What are cashback sites and how do they work?

Cashback sites receive commission from retailers for advertising them on their site and for sending shoppers to them.

The cashback site then gives a percentage of the commission back to you, the shopper, while the rest makes up its profit and covers costs.

As a customer, you can get cashback for changing your utility provider, grocery shopping, buying electricals and even on clothing and shoes.

By shopping online via cashback sites such as TopCashback and Quidco, and clicking through to your chosen retailer, rather than directly via the retailer’s site, you could make hundreds of pounds a year, as long as your transaction tracks (your visit and purchase is recorded).

Here are a few offers currently available on TopCashback:

• £110.25 cashback when you take out a Sky TV and broadband package
• £225.75 when you take out a valid life insurance policy via Confused.com
• 5.25% cashback for new Wallis customers making a purchase.

When you register on a cashback site, you can opt for a basic free membership or you can opt to pay £5 from your earnings for a premium/plus account which promises to give additional bonus rates to your transactions.

Once you’ve received the money into your account, you can choose to withdraw it via bank transfer, Paypal or via high street vouchers.

‘My broadband has pretty much paid for itself’

Simon Barlow joined TopCashback in 2010 and to date, he has earned £5,600. He has made £877 in 2016 alone, which he uses to cover unexpected bills and treats such as meals out and weekends away.

The 38-year-old from London says his strategy is to check the cashback site first when looking to buy an item or change a supplier. “Things can change daily, especially with broadband and TV suppliers. So I check the cashback site and then have a look through the comparison sites and with a supplier directly,” he says.

He then clears his history/cache so the cashback tracks properly. This is important because sometimes when you go direct to a retailer first, the cashback site does not record your transaction. By clearing your history, the cashback site can see that you’ve gone via it to the retailer (more on this below).

The commercial promotions executive says he has come close to getting items for next to nothing. On his broadband, he received £220 cashback, then a £100 voucher from the provider. As the monthly bill for the service was £28, the deal pretty much covered the cost of the annual service.

He says: “It’s not just energy, TV and broadband – most online versions of high street stores plus some banks and insurance providers are all there offering varying amounts. For the sake of clicking through via the cashback site it makes total sense.”

However, he cautions that cashback can take a while to show up: “Retailers can have a validation period from a few days to a few weeks or months. So factoring it into a major purchasing decision isn’t wise.”

‘I got £300 towards my honeymoon’

Adam Kirby, 37, has been a member of TopCashback since 2010 and has earned £4,900 using the site. He first heard about it from a friend, and his initial thought was it was “too good to be true”. When he got his first payout, he wondered why he’d not used it sooner.

The Londoner’s strategy is different to Simon’s as he researches the cheapest price of a good first then checks TopCashback to see if he can get any money back from the transaction. But he says that if the cheapest good isn’t listed on the cashback site, he might go to another retailer where it costs more but where the cashback makes up the difference, if not a better amount.

The cameraman has just booked an £8,000 honeymoon via Expedia and by going through TopCashback, he was able to earn 3.5% cashback, putting nearly £300 in his pocket.

His advice is never to buy or book something purely for the cashback. “If the retailer’s listed, then boom, it takes five seconds longer and even if it’s £5 or £10, it all adds up.”

‘The cashback may be small but it can pay for your lunch’

Michael Millington, who lives in Staffordshire, uses Quidco and says car and home insurance is “the biggy” for cashback but you can also make big savings with utilities. Using Quidco Compare to get the cheapest quote, he then receives £20-£30 cashback but some insurers have more attractive offers of £80-£100 cashback.

“I once got a home and contents cashback offer of £100 and the insurance itself only cost me £136.70, so effectively I got my home and contents insurance for the year for £36.”

The 52-year-old said your mantra needs to be: “Can I get cashback for this?” You may find it for the same price at another online retailer but that retailer offers 10% cashback. If the item is £100 that’s a tenner for the same thing.”

He adds that you can also earn cashback in-store so if you register your cards, you can get cashback on impulse shopping so there’s no need to click through online.

One other nugget of advice is on big purchases. “The cashback % may be small, maybe only 1% but if it costs £500 that’s a fiver – a fiver you wouldn’t be getting otherwise. It pays for your lunch!”

TopCashback’s top tips to maximise your earnings:

1. TopCashback offers on-card deals which allow members to shop in-store rather than online. Just register your debit or credit card, browse the site and activate the in-store offers.
2. The Snap & Save function allows you to earn cashback on a range of everyday grocery products bought in-store. Once you’ve bought an eligible item, take a picture of the receipt and upload it to the website or via the app and the cashback will be credited to your account.
3. Cashback usually tracks with no problem, but there are certain things that can upset the system. You should visit retailers via TopCashback and not click to any other sites before buying. You should also check your computer is set up to record cookies in the internet browser and clear cookies if you’ve been browsing around before going to TopCashback.
4. If you do experience a tracking issue, report it to TopCashback’ where it will look into the issue and speak with retailers on your behalf to recoup the missing cashback.

Quidco’s top tips to maximise your earnings:

1. The Quidco App: When you’re out and about you can activate in-store cashback offers to make the most of over 50 retailers that offer cashback when you buy in-store with your registered card.
2. Quidco Compare: The big ticket items (cashback wise) are almost always utilities and insurance. You can compare car, travel and home insurance through Quidco Compare (as well as broadband and energy) and you’ll earn extra cashback in the process.
3. Reward Coins: Certain retailers also offer reward coins when you make a purchase of over £10. Premium Quidco members could earn up to an extra £70 in rewards (£35 for basic Quidco members).