I have a Roland GR500 guitar with out the synthesizer box. i was never able to find it. I just have the guitar. Im looking to sell it to maybe buy another fender or maybe my first gibson. Does anybody know what the price range i can get out of Just the guitar alone with instructions and a case and where i should sell it? The guitar is in pretty good condition. No major dings or scratches being it is from the late 70's.