If I told you I could give you £100s a year with no debt and very little hassle – and all you need to do is change your plastic – would you? If the answer’s yes, read on, as now is the perfect time to grab a cashback credit card. For many, it’s an easy and lucrative way to boost your income.

Now’s the moment because the top deals will boost cashback for the first three months you have them. So apply NOW and that boost lasts for most people’s highest-spending period – Christmas and the January sales.

This can be serious cash. As one of my Twitter followers (@martinslewis), NM, told me: "Our cashback cards earned us £250+ last year." This isn’t unusual, I’ve even heard of some big spenders going over the £1,000 mark. So here’s what you need to know:

1. Never pay interest on a cashback card

Cashback cards only win if you set up a direct debit to repay IN FULL every month. If not, don't go for a cashback card, go for the best 0% for spending deals (see www.mse.me/ spendingcards).

2. Now you've got a debit card that pays you

Your credit card is now effectively a monthly-billing debit card, provided you stick within the limit. Use it for ALL spending instead of cash, cheques and debit cards. If you're in a trusting relationship, add your partner as a second cardholder, so their spending earns too.

3. Huge 5% cashback over Christmas and January sales.

The no annual fee www.americanexpress.co.uk Platinum Everyday card pays newbies 5% for the first three months until January, up to a maximum £100 back in that time. Though if you fail to fully repay, it's 19.9% rep APR.

After the 5% ends, the rate's up to 1.25%, depending on how much you spend. It requires a decent credit score and household earnings of £20,000+.

4. You'll get the cashback in time for next Xmas

With the Amex card your cashback is paid on the anniversary of the account opening. In effect, it's actually subtracted from your spending. For example, if you owed £400 and had £200 cashback, you'd be charged £200. So open one now and it’s a boost for next Christmas.

5. Top card if you’ve a less than perfect credit score

To get most cashback cards you need a good credit score. Frustratingly, the only way to find out for sure is to apply, but that involves putting a mark on your credit file (whether you’re accepted or not).

To find your likely odds of acceptance for many different cards, I’ve built an Eligibility Checker tool at www.mse.me/CashbackEligibility, which tells you your chances without any impact on your credit score.

For those with a lower credit score, the card most likely to accept you is the www.capitalone.co.uk Classic Extra. It pays 0.5% cashback, plus a £10 yearly bonus if you manage it well, paid each January. As it's primarily marketed as a card to rebuild credit for those with weak histories, even some with past CCJs or defaults can get it. Though you must repay IN FULL each month, or it's a hideous 34.9% APR.

6. Best for motorists: 3% back on fuel spend

If you drive or commute a lot, check out the www.santander.co.uk Santander 123 credit card. It pays 3% (max £9 a month) on petrol, diesel, rail and Tube spending plus 2% in department stores and 1% in supermarkets. The cashback is paid monthly.

Though it does have a £24 annual fee (unless you’ve the 123 bank account, in which case the fee’s refunded in the first year), which is why it's only suitable for those who drive a lot. As always, repay IN FULL or it's 18.9% rep APR.

7. Free £100 M&S, Amazon or Boots voucher

Though not strictly cashback, if you're accepted for the www.americanexpress.co.uk Gold charge card and spend £2,000 in the first three months, you get 20,000 Reward points, convertible into £100 vouchers for the likes of M&S, Boots and more (it can change). Even better, the freebie comes as soon as you hit the trigger spend, so probably in time for Christmas if you're a high spender.

It’s important to note this is a charge card, not a credit card. That means it's designed so you must fully repay each month, or you’ll get a £12 charge and a default on your credit file. It’s also important to point out this has an annual fee of £125 - but it's waived in the first year, so unless you want to pay it, make sure you cancel it by then.

8. It only pays cashback on spending

Withdraw cash or balance transfer to the card, and you won’t get cashback.

9. Cashback card golden rules:

These three facts are so important they’re worth reiterating:

a) Always use a monthly direct debit to repay IN FULL, so it's interest-free.

b) Don't use it as an excuse to overspend.

c) Ensure you've got the cash to repay monthly.

10. Spending on a credit card is huge extra protection

By law, buy anything costing £100 to £30,000 and pay, even partly, on any credit card (not debit or charge) and Section 75 laws mean the lender's jointly liable. So if an item's faulty, or the retailer goes bust pre-delivery, you can get money back from the card firm.

Want Christmas supermarket delivery?

Book ASAP Xmas week grocery delivery slots for turkey, Christmas pud and hot cakes go like, er, hot cakes. I've got a full store-by-store list of slots available at www.mse.me/xmasdelivery

Free 2014 Trex recipe calendar

My site users love this nice calendar with food pics and yummy recipes. Just sign up at www.trex.co.uk/2014calendar before 20 Dec.

Book flights 59 days in advance

There's a new nerdy fun tool to help you grab a cheap flight. Do a search via flight comparison www.momondo.co.uk then click the 'Flight Insight' tab if available for your route. It'll tell you nerdy facts like you should book 59 days in advance or Tuesday's the cheapest day to travel.