Per the archives this is the equivalent of a single stage QT-5, which is splash instead of pressure lubed and makes 17cfm at 100 Psi and 900 RPM. Market price for a verifiably well running QT-5 single phase of that vintage in California would be in the $6-700 range but not sure if that would be the same out east.
Sounds high to me but not crazy high. Especially because these days buyers want to pay less than half the asking price.
How was everything else priced? They might be negotiable. You can always offer less and go from there.
Zek is spot on. The 'Air Master' was the forerunner of the QT-5. He is also spot on pricing also, if in good running condition. They are a little on the loud side though, I had one when I used to work out of my 2 car garage. I ended up selling it and buying a Saylor-Beall 705 which is MUCH quieter.
hmmm, i'm used to a Makita 2400 in a 2 car garage, very quiet. Would not surprise me if she would go to $200-300 for it, but a good price is quickly forgotten if the thing is so loud it's uncomfortable to work.
If you can get if for that price just do it and spend $100 on an intake muffler which should quiet it down quite a bit (albeit not to Saylor Beall 705 levels.)