Where can you find history of antique vacuum cleaners made by Feeny Mfg Co?

I have a Model C I was planning on selling soon. It is complete and working as good as a 90 year old vacuum can.

I'm actually on here to determine it's value.

I don't have any pics presently but what would you offer for a fairly clean working one with the front Feeny label a little scuffed off but easily legible?