Guns that got away? Throughout the years, $600 or so seems to have been my breaking point for being "too much" to pay. Of course some of these prices are from 25-30 years ago. In no particular order:
Colt 7-1/2" SAA in .44 Special, $600. At the time I thought that the only proper caliber for a SAA was .45 Colt.
USFA 7-1/2" in .32-20, $700. I thought about it but naaah, just didn't want that little oddball caliber.
S&W Model 25 in .45ACP with a 4" barrel for $400. I wasn't much into Smiths at the time so I have no idea if it was a unicorn factory 4" barrel or cut down, but it sure looked beautiful.
Model 58 with a Model 29 4" .44 Magnum barrel and cylinder, $700. I had just bought a Model 22-4 and a 21-4 and didn't think I could afford another fixed sight big bore.
A Webley-Scott .455 self-loading auto pistol for $600. I was really into foreign WWII military autos at the time but they were more in the $300 range generally.
A stack of C96 Mauser Broomhandle carbines in wooden boxes for $300 each. These were made up by Fed Ord using receivers from China and were in 7.63 caliber, and I didn't want it if it wasn't a 9mm. I thought they were kind of rough but I saw them being passed off as originals 20 years later for thousands of dollars.
Shansei .45ACP Chinese Broomhandle that went for $700 in an online auction a few years ago.
Nicely refinished 3-1/2" Registered Magnum at a Tulsa Wanenmacher show a couple of years ago. Priced at $2800 and a guy was writing a check for $2500 for it, just as I was walking back up to offer that much for it. Probably my last chance to own an RM for a price that I could stand to pay without bleeding from the ears.
The list goes on. However I have a couple of gun safes full of stuff that I did not let get away....