Im looking to buy my first benz. I will probably buy a c300 thats a couple years old, but i have heard that they are very expensive to repair. for this case i want to get a warranty

1.are there different levels or types of warranys you can buy?
2.If you can how much money are they typically for each?
3.what do they cover in the warrantys
4. what do they NOT include in the warranty (like parts they won't pay for)
5. how often are the parts not covered usually last before needing to be replaced