It makes sense to look into the details of a product before buying it - but that can be tricky when the headline reads one thing and the small print another.
Here are some examples of where products might not be everything they first appear to be:
1. PPI
Payment protection insurance, or PPI, is usually sold alongside a loan and can pay out extra money to cover monthly repayments if the borrower falls ill or gets the sack.
But PPI has been looked into recently by the Financial Services Authority (FSA) - the body in charge of policing the banks and other lenders - as some providers were not giving enough information about the cover to their customers.
The FSA found that many lenders do not tell clients what their PPI covers or even why they need to buy a particular policy in the first place.
Some PPI providers have stopped selling the insurance completely, while the FSA found others still weren't up to scratch and might still be letting employees sell PPI who haven't got any idea what it is or why it's useful.
2. Extended warranties
When you buy pricey electrical goods such as computers, TVs and digital cameras, you'll usually be offered an extended warranty at an extra cost - often when you're already at the till and just want to get out of the shop quickly.
But it might pay to stop and think, as statutory rights mean anything faulty should be repaired or replaced for free, notes Citizens Advice.
The advisory service adds that home insurance policies usually cover accidental breakages too, meaning extended warranties are a waste of money if you've got decent contents insurance.
Extra rules were brought in back in 2005 to try and stop customers being sold extended warranties they don't need.
Susan Marks, social policy officer at Citizens Advice, said at the time that members of the public "have a right to goods that work" without shelling out for a worthless warranty.
3. Mortgage exit fees
With interest rates higher than they've been in years and fixed-rate mortgage deals coming to an end, people might be looking to remortgage to save money.
But figures from mortgage broker John Charcol show it could be a costly move, as the average charge for quitting a mortgage before the end of the agreed period stood at £180 as of October 2007.
Other penalties, including early repayment charges and limits on paying off extra each month, are also sometimes made - trapping the homeowner into a deal for even longer.
Industry body the Council of Mortgage Lenders predicts that the number of repossessions in 2008 will be half as much again as in 2007 - with 45,000 families at risk of being made homeless.
4. Premium telephone numbers
Premium-rate phone lines have been hitting the headlines recently due to the investigation into phone-in scams operated by ITV and other channels.
An investigation carried out by Deloitte found that calls were taken sometimes when the competition had already closed, while some winners were picked without any calls being taken at all.
It's not just the TV channels who are raking it in on premium lines - you could find yourself faced with a premium-rate number the next time you call a company for help.
Virgin Media is an example of this, charging 25p a minute on top of a 10p connection fee - the company says that if a call goes on for more than 20 minutes, an employee will phone the customer back.
But that might not be much of a comfort when you're already a fiver into your phone bill.
5. 'Guaranteed' savings rates
Some savings accounts offer a 'guaranteed' interest rate, based on the Bank of England's base rate. And that's higher than it's been in years right now.
But the guarantee quite often includes a rule that the interest paid will always remain below the base rate and will actually go down if the rate drops in the future.
Linda McBain, head of banking at Investec Private Bank, points out the problem with this. "Why would anyone choose a rate which is guaranteed to be below the base rate?" she asks.
Ms McBain adds that there's often a 12-month limit on the rate anyway, meaning the saver must switch to a new account to carry on getting a decent amount of interest.
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