Interesting question. The most I've paid is - I think - £160 for a nearly mint 1961 Webley Mk3 a couple of years back. It was a gun I'd always wanted, & I was quite happy to pay that. It gives me much more pleasure to use than a new Weihrauch I paid 2x that for!
After the Mk3, last year I thought I'd look for an early AirSporter Mk1 or 2. Put some ads out, & was offered stuff Steptoe would have refused. To my mind, 95% blueing does not mean 95% is missing. Eventually, this year, settled on a very tidy Mk 4 A/Sporter, which the seller had honestly described & I had no problems with paying the asking price.
Still after an early Sporter, but not in a hurry.
Webley Mk3 x2, Falcon & Junior rifles, HW35x2, AirSporter x2, Gold Star, Meteors x2, Diana 25. SMK B19, Webley Senior, Premier, Hurricane x 2, Tempest, Dan Wesson 8", Crosman 3576, Legends PO8.