2010 Prius IV: Is this a good deal?

My son, who is a senior in high school, received a scholarship to study Electrical Engineering. I told him if he received a scholarship, I would give him my 2005 Corvette (and I would take his college fund and buy a newer one ). His interest in EE is so he can study and work with renewable energy, so he has decided he wants a Prius instead of the Corvette. I'm an old gear head, so a paternity test may be in order. Just kidding.

He wants a Gen III with navigation and leather. I have found a 2010 Prius IV with 29,000 miles and the private party seller said he would take $20,000 (asking $22,000). He said Carmax has offered him the same price and he'll sell it to them before he goes any lower. He said that his father (he's selling it for his elderly parents) backed into a car in a parking lot that required a repair, but he thinks that's the only blemish on the Carfax. The title is clean. He said the interior is perfect, never smoked in, and still smells new. It has a prepaid, transferable maintenance agreement...whatever that is.

I've looked at a lot of cars and seen a lot of asking prices, but I don't know any actual sales prices. Assuming the condition is as he says, is $20,000 a good price for this car?

 

We drove 12 hours round trip yesterday to pick it up. The Carfax was flawless, as was the interior of the car. There were a couple paint chips on the front and a scuff or two elsewhere, but overall it was a very nice car. The parking lot accident cost less than $500 to repair so it was very minor. The maintenance agreement is simply a prepaid oil change/tire rotation agreement. It has another 2 years and 24,000 miles on it...no huge value but a bonus nonetheless. My son absolutely loves the car. Thanks for the input.