You just never know with cars. I had a 1990 Jeep Cherokee 4WD 5-spd that my wife drove for 10 years and we never had an issue with it.
I paid 3K for my first Insight Turtle (which my son now owns and re-badged "Dr. Horrible", and is right ahead of my in the mpg challenge with). That one had 200K miles, leather seats, a real nice DVD system that I turned into a rear view camera, newish Michelin Energy Savers, newer paint, replacement IMA battery, dark tint and was an all around nice car.
I paid 4,500 bucks for Ron Burgundy, which came with 111K miles, sunroof, black leather interior, shaved doors, custom paint, dark tint, newer IMA battery, Hybrid Automotive grid charger, hardwired radar detector, 4-spkr Kenwood sound system, solar 12V battery charger, and newish OEM RE92s, and is the nicest Insight I've ever seen in person.
Neither car has had a battery failure, neither has the downshift grind, or leak any fluids. Both have functioning AC, all the electronics work, etc . . . there are deals out there if you pick the car carefully and know what to look for when you go to test drive one.
If you're looking for one, here are a couple of examples in your area, one being a nice sub-100K miles example:
Honda insight plug in hybrid 61 mpg
2006 Honda Insight