There is a well known saying that you 'don't get something for nothing'. Well, in the world of credit cards, this is not always the case.

With cash back systems, credit card holders are rewarded for paying off their balance in full, on time every month with a rebate of around one per cent of the value of their purchases. In some cases, introductory offers lure in customer s with cash back rates of between two and five per cent.

Effectively, this means that you are being paid for spending money. A person who spends £10,000 a year on their card could end up with £100 for choosing to do so with their plastic.

Money advisory website Fool.co.uk says: "It might not sound much but it's free money for doing nothing more than you do already so whenever possible, buy everything - even your smallest purchases - on your credit card for maximum cash back."

Who suits the cash back scheme?

According to Money Saving Expert Martin Lewis there is one golden rule when considering going for a credit card with a cash back option:

"Only go for cash back if you're never, ever, ever charged interest. This means you must always pay the card off in full each month."

He advises setting up a direct debit that clears the card's balance at the end of every month to ensure that this happens.

If you are the kind of credit card user that does not clear their balance or make payments then these type of products will not be for you.

This is because cash back deals are an incentive to spend more on the card. For someone who does not clear their account each month, the more they spend the more interest they will be charged on their purchases.

Hence, this type of consumer will actually end up paying more for their purchases and make no money whatsoever, which is what the credit card companies are banking on.

Where are the best deals?

Martin Lewis highlights the Amex Platinum card as the best over deal, which offers a cash back rate of five per cent for the first three months and a rate of 1.5 per cent thereafter.

This means that cardholders will receive five pence back for every pound they spend initially, which in the long run could prove to be lucrative.

However, Lewis does warn that Amex is less widely accepted than Visa or Mastercard, so this card may have its limitations, especially when making purchases with small retailers.

Other alternatives on the market are the Egg Money card, which offers one per cent cash back on everything the card holder buys, though it has capped its annual payout at £200.

The Abbey card also offers a good deal, with a five per cent rate on supermarket shopping purchases at Sainsbury’s, Tesco, Asda, Morrisons, Waitrose, Somerfield and Co-op stores. It should be noted that sneaky petrol purchases will not be included in the scheme.