I think the prices seem fair. I personally feel we are kinda under valuing our cars. I wouldn't consider selling mine for less than 20. I love it. The gxps stay up in value or even higher than what they sold new if it has really low mileage. Parts can be expensive and can be hard to find. Demand for our cars is as high as it was 3 years ago and kids love the looks, so it seems the demand for our cars will be around for quite some time.
Also. For the cars listed and thier prices. Obviously mods, condition, features, accidents and repairs it may currently need or will need soon will play a factor in the value.
Good luck. At least you have a few to choose from
PBM GT W/SPORT PACK
Pat G tune
EXHAUST: BADLANDZ CUT OUTS W/ X PIPE AND RESONATOR DELETE
KOOKS 1 7/8 mids and HFC's (coated)
PONTIAC EMBLEMS REMOVED. HOLDEN TRUNK LOGO ADDED.