High mileage or 10+ year old hybrids are cheap now. Gas is cheap, so the mpg incentive isnt there for the market. Combine that with a fear of battery problems and you have a great market for a savy buyer.
I recently picked up a 2004 prius with 225k miles for $800. It was a crap show of a vehicle, but the important parts worked. I had to pull the seats, panels, and carpets out to clean that disaster of an interior, but the sweat equity came at a time when my hours from work were low. The dashboard display was also broken, so I had no gauges until I sent the gauge out for repair at $140 via ebay vendor. It gets 45mpg with normal city driving, or 50 if I really work it. That is without playing the mpg games the hypermiling folks do, which can make you a target for road rage. The bumper covers are shattered and held together with duct tape, but this car was bought to be an appliance. Damaged cosmetics makes it less likely of a target for break in or vandalism in rough areas.
I see much better "turn key" condition Prius of similar age/mileage for about $3k-4k all the time, which is still cheap when you consider a same year corolla is going for more right now. civic hybrids also seem incredibly cheap, but seem to have transmission issues.
There are lots of maintenance quirks that are well documented for the advanced DIY person. Cleaning the hybrid battery fan is a big one, on mine the fan was nearly blocked with lint. From what I read the pre- 2004 models should be avoided, because of battery cooling issues. The 2004 onwards are incredibly reliable. 2006+ are more desirable, in terms of electronics packages (aux input for sound, rear camera, etc)
if you see a good price on a 2003-2008 corolla (not the S model though) with a stick shift, you can get very respectable 35-40 mpg with a simpler car. I've simply been seeing them priced higher than the prius in the used market. Scion XA and Yaris also qualify, with the same notes. We have a 2006 corolla CE stick shift, and love it. That car will move with us, the Prius will be jettisoned to craigslist (corolla is in much better shape).
Avoid buying a prius if you are a stereo nut. The OEM system is integrated into the very being of the car, you won't be happy trying to bring in aftermarket anything.
Mine also had a "new battery". The prior owner had paid $300 (!) to have a new 12v battery installed, the hybrid battery is original as far I can tell.
If you are very tall, Prius ergonomics can be weird. I am 6'0 with 32 inseam, and find the elevated seat height discomforting at first. I can not comfortably sit in the back, my head hits the sloped ceiling. If you and your 3-4 passengers are on the heavy side, you can easily overload the payload of the car, which is less than 1000 lb capacity. 4 of me would be very close to overload.
