Citizens Advice is urging a ban on cold-calling by claims management companies after a survey found nine out of 10 people have been contacted in the last year.
A month-long survey found 62% of people had been "pestered" by calls, emails and spam texts within a single week, with 72% of those from firms seeking their cut of the £2 billion payment protection insurance (PPI) compensation fund, according to the consumer advisory service.
A wider report based on a survey of 300 people and analysis of 288 client cases about problems with claims management companies found 90% had been contacted "out of the blue".
Citizens Advice is urging consumers to put the phone down on PPI cold-callers and go straight to their bank to make a claim.
The report found that the companies take around 25% of a successful PPI claim in charges, with customers spending on average more than £1,100 in fees for something they can do themselves for free.
One Citizens Advice Bureau saw a client who paid more than £4,000 in charges, while some firms were charging up-front fees of £600 without being clear if the consumer would get a payout.
One in five Citizens Advice clients was led to believe they could make a claim for PPI without having or being mis-sold a policy, with one in four finding themselves in debt or financial difficulty after paying fees to a claims company, according to the report.
Citizens Advice said its consumer service handled more than 4,800 queries about claims management companies offering PPI compensation services in the last seven months.
Citizens Advice chief executive Gillian Guy said: "People should give cold-callers the cold shoulder and go direct to their bank if they want to make a claim for PPI. We're advising them to ignore any unsolicited calls, texts, letters or emails from claims management companies.
"These firms are intimidating people in their home and wasting a lot of people's time, and in some cases money when they make a claim and nothing comes of it. They're not up front with their customers about fees, are charging excessive costs and aren't getting people the payout they deserve."
10 of the biggest consumer rip-offs
Call to ban PPI claims cold-calling
Using a mobile phone to make and receive calls, send texts and browse the web while abroad can be extremely costly – especially if you are travelling outside the European Union (EU), where calls can cost up to 10 times as much as at home.
To avoid high charges, Carphone Warehouse suggests tourists ensure a data cap is in place, use applications to check data usage, turn off 'data roaming', avoid data-intensive applications such as Google Maps and YouTube and use wi-fi spots to update social networking sites.
Payment Protection Insurance (PPI) is supposed to help people to continue meeting their loan, mortgage or credit card repayments if they fall ill or lose their jobs. However, policies are often over-priced, riddled with exclusions and sold to people who could not make a claim if they needed to.
At one point, sale of this cover - which was often included automatically in loan repayments - was estimated to boost the banks' profits by up to £5 billion a year.
Now, though, consumers who were mis-sold PPI can fight back by complaining to the bank or lender concerned and taking their case to the Financial Ombudsman Service (08000 234567) should the response prove unsatisfactory.
It could be you, but let's face it, it probably won't be. In fact, buying a ticket for the Lotto only gives you a 1 in 13.9 million chance of winning the jackpot.
With odds like that, you would almost certainly be better off hanging on to your cash and saving it in a high-interest account.
No-frills airlines such as EasyJet may promote rock-bottom prices on their websites. But the overall fare you pay can be surprisingly high once extras such as luggage and credit card payment fees have been added - a process known as drip pricing.
Taking one piece of hold baggage on a return EasyJet flight, for example, adds close to £20 to the cost of your flight, while paying by credit card increases the price by a further £10.
It may therefore be worth comparing the total cost with that of a flight with a standard airline such as British Airways.
Cash advances, which include cash withdrawals, are generally charged at a much higher rate of interest than standard purchases.
While the average credit card interest rate is around 17%, a typical cash withdrawal of £500, for example, is charged at more than 26%.
What's more, as the interest accrues from the date of the transaction, rather than the next payment date, costs will mount up even if you clear your balance in full with your next payment.
Supermarkets such as Tesco and Asda often run promotions under which you can, for example, get three products for the price of two.
However, it is only worth taking advantage of these deals if you will actually use the products. Otherwise, you are simply buying for the sake of it, which is a waste of your hard-earned cash.
Buy a train ticket at the station on the day of travel and the price is likely to give you a shock - especially if you are travelling a long distance at a busy time of day.
However, you can cut the cost of train travel by 50% or more by going online and making the purchase beforehand - especially if you book 12 weeks in advance, which is when the cheapest tickets are on sale.
Other ways to reduce the price you pay include avoiding peak times and taking advantage of so-called carnet tickets, which allow you to buy, for example, 12 journeys for the price of 10.
Most High Street banks offer packaged accounts that come with monthly fees ranging from £6.50 up to as much as £40, with a typical account charging about £15 per month.
Various benefits, such as travel insurance and mobile phone insurance, are offered in return for this fee. But whether or not it is worth paying for them depends on your individual circumstances.