I need help priceing one of my bikes

[anthonygs1000]

      yeah I passed my road test ,the first time  I was so scared and I don't know why, It was a cake walk, now  today I am   FREE . Now I want to sell my  stock 1990  gs500 it has 22k for miles  and  needs  tires  it has a couple small dings in the tank it could use a little paint work this bike runs flawless  rides great what should I ask for it ? Help (I want to start riding my black one. the picture of the bike is in my profile photobucket hmtl) the red one is going to be for sale P.S. I took the chin spoiler for my other bike