Many people do not realize that the later compact version of the Prizm was nearly identical to the Toyota Corolla. There were small cosmetic differences, and the Geo lacked a front stabilizer bar. Aside from that, they were the same car. Even today, NADA prices a 2002 Prizm nearly $2,000 from a 2002 Corolla, despite the fact that they are nearly the same car. I guess the stigma of driving a Geo/Chevy means a lot to some people. Astute car buyers should be aware of this huge price difference and seek out the value of the Geo.
With an inline 4 cylinder engine, the Prizm could get 32 to 38 miles per gallon, which isn't bad for a 4 door sedan. There were a total of 3 generations of this car, with only the first two sold under the Geo name.
For the most economical mileage, look for the Prizms with a 5 speed manual transmission.
These cars are readily available on the used car market, and I've got to say that there are some super buys out there. People seem to be unloading these like they would any other used Geo or Chevrolet, even though they have the same reliability as a Toyota. I think these make a great first car for a teenager, because they aren't particularly fast (so you won't have to worry as much about reckless driving), they are reliable (less worries about junior getting stuck somewhere), and they get great mileage (so junior won't be begging to borrow cash to buy gas all the time). You can find plenty of these listed on eBay. Be sure to check out those listed as Geo's and the Prizms listed as Chevys.