is the 2011 toyata prius a good model

Generally speaking Toyota is a very good vehicle! But this one is 10 years old and a lot can happen to a very in 10 years! Do your homework before you buy. Get a vehicle history report such as Carfax. Look for accidents, multiple owners, repeat service visits for the same repair, etc. Also look for regular maintenance visits at reputable service facilities. Dealer servicing is best, in my opinion! Have the vehicle inspected by your mechanic if you're not vehicle savvy. Buying any used vehicle is a gamble. But, as I said, Toyota is a good vehicle and doing your homework will make it less of a gamble. Hope that helps! Jim

Old hybrids tend to have expensive battery failures.

Think about it this way. That car has had 11 years of use, abuse and probably neglect and now the owner does not want it anymore.