As 'they' say, a seller's thing is worth what a buyer is willing to pay.
This is primarily a collector's enjoyment site, not really an evaluation source.
There are bucketloads of Kirbys that are regularly listed on eBay - dare I say more than any other vacuum, by a size-able margin.
Monitor Kirbys for a few weeks or a month on eBay, CraigsList etc keeping track of year and model and condition to get a ballpark value for not only asking price but what sellers are actually getting.
When you are ready to plunge in, compose a comprehensive description of what you have with plenty of detail pictures,
Used Kirby dealers or at other shops are never a true indicator of what a used vacuum is worth - they have overhead but certainly use them as a guide.
When you have a target price in mind, low-ball your reserve if you select Reserve). or offer a Buy-It-Now option. Or to simply get rid of it start tjhe bidding at $.99.
On any given Day vacuums sell either low, medium or surprisingly high depending on condition and the crowd watching your auction.
PS. the provable rebuild papers are definitely a plus in your favour.
Good luck!
