Specific coverage and fees can vary significantly between product protection plans, and the process for filing and handling claims can be pretty different (and often very cumbersome) depending on the company servicing your plan. If you can't find simple instructions as to how you'll file a claim and what it will cost you, steer clear of that provider. Before you purchase a protection plan, you should know exactly what it will cost, what the process is to submit your claim and how to track the status.
At the very least you should know if there is a deductible you'll be required to pay when you file a claim, and if there are any additional fees you'll be charged based on the type of incident, specific product damage, etc. For example, you may not realize that AppleCare requires an additional deductible if you damage the screen of your device. Check out this article to learn how to calculate the cost of an extended warranty.