Fully investigate an extended auto warranty's deductible before signing on the dotted line. Consider not only its amount, but also whether it's per visit or per repair.

With a per-visit deductible, each visit to the shop will run you a fixed amount, regardless of how many parts are repaired; a per-repair deductible applies to each serviced part. What sounds like a minor difference may, under certain circumstances, have a major impact on your wallet.

If, for example, you've got a $100 per-repair deductible and you take your car in to get the air conditioner, fuel pump and alternator repaired, you'll be out $300. Had you opted for a per visit deductible, those repairs would only have cost you $100.

There are still $0 deductible warranties. You will have to pay extra for this type of extended auto warranty, but if your circumstances become such that you have to take your car in frequently, you'll find that this policy more than pays for itself.