I tend to agree with you and do not purchase extended warranties on many things....but....in the Volt....I though of it as cheap insurance as there are MANY electronic/computerized systems in this car ....lots of potential for an expensive problem or problems.....luckily (and I really hope I do not jinx myself here).....the only warranty issue I have had in the entire 5 years/52K miles I have owned the Volt (well besides the cricket-y sounding brakes at near complete stops.... in the cars infancy.... that was taken care of with some extra lube or something....still not exactly sure what the dealer did but it went away so....) was the service high voltage system error with a failed coolant sensor....seems to be a common problem (so I have read)..........We can't tell you whether that's a good price or not because you didnt' tell us whether you have a base or Premium Dan what options you have. The MSRP can vary by over $5k.
I'm very anti extended warranties. Just put the money you would have spent on the warranty in the back and use that for any car repairs. The odds are that you won't need to replace more than that amount. The only exception is if you have a long history of cars falling apart on you. If you are that unlucky, then maybe an extended warranty is for you