PPI can be a useful product - What Is PPI?
Payment Protection Insurance is an insurance product that protects you from payments you have to make should you be unable to make those payments. Typically it covers you if you are made redundant (but not if you get fired), if you are unable to work due to illness or if you have an accident. It can be taken out to cover any kind of credit that you have to pay for. Typically for mortgages, loans and credit cards. It can also be taken out on store cards and even to cover the payment of other types of insurance such as life insurance.
What Are PPI Claims?
Although PPI can be a useful product the FSA (Financial Services Authority) that regulates the selling of financial products has deemed it to have been miss-sold a lot over the past 6 years. It has been miss-sold in the following ways:
 Customers were being sold PPI that they would never of been eligible to claim on anyway because they may have been self employed, been in a job that is classified as dangerous, on a short term contract, been too old or have pre-existing medical condition. In fact if you checked the small print in some policies you would find lost of exclusions. Some don't cover you if you are of work ill with back pain or stress which are 2 of the biggest causes of absence from work.
 Customers were being charged up to 10 times what the products is actually worth!
 Finally people were sold PPI in a way that is not consistent with FSA guidelines. Either they weren't aware PPI was included with their credit, they thought they had to buy the product or that it would increase their chances of being approved for credit or high pressure selling techniques were used to sell the product. E.g. "we would like to approve you for this credit but we are worried about what would happen if you were to lose your job...".
If any of these apply to you then you can claim back what you paid, plus interest and in some cases PPI compensation for excessive miss-selling. Currently 90% of claims are valid so if you do have PPI that you have been paying the past 6 years there is a 90% chance it was miss-sold unless you shopped around and bought it independently of your mortgage / loan supplier. In some cases customers can even claim PPI if they have actually made a claim on the insurance.
What Can You Claim For?
The first and biggest sum you can claim is usually everything you paid out in PPI since 2004. Banks typically would charge you a lump sum for PPI at the beginning of your loan or mortgage. This means you were charged interest on the PPI at the same rate at your loan / mortgage. If you took at a 5 year loan with some of the worse PPI offenders then PPI could work out at up to 25% of the total you paid back. So a 7,500 loan over 5 years with PPI you could end up paying back up to 13000. 3000 of which would be PPI plus interest! You would of only had to pay 10,000 without the PPI.
On top of this you may be entitled to a standard rate of interest on the money that should have been yours, usually 8% per annum. Finally in cases of excessive miss-selling you may be entitled to compensation for the whole ordeal as it could of led to serious detrimental debt problems and even bankruptcy.
How Much Can You Claim Back?
If you had a breakdown each month of what you paid out in PPI since 2004 then you can add all this up to give you a minimum estimate. Also if you are still paying for this over priced PPI then you can cancel the policy which will reduce your monthly outgoings. You could then, if desired, sign up to an independent and reasonably priced PPI policy. This policy would be paid each month not in one lump sum with interest.
Alternatively if you don't know what you actually paid in PPI, to get a ball park figure it is 20% of what you paid back in loans, mortgage and credit cards between 2004 and 2010 that had PPI. So if you paid back on average 500 which included mortgage and credit cards, over 6 years that is 72 months, 72 x 500 is 36,000. This would probably equate to 7,200 of PPI.
PPI Claims Management companies that I have spoken to say they have recovered 20,000+ for some clients. Especially if you have a lot of debt that you "juggle" between credit cards and a big mortgage. The biggest claim I am aware of was 41,000 for a single client which was PPI spread out across 1 loan and 3 credit cards. 41,000 of money that the client would not have had if they had not decided to pick up the phone and make a claim.