It's not how the survey is broken down, but I get functional reliable pistols in the $250-$350 OTD range very often.
I'll occasionally pay or trade for a fancier target revolver, but none of my SD handguns cost more than $400 OTD.
My Makarov was $89 in the late 80's and my FEG Hi-Power was $200 - they both still work just fine and there's a 99% chance they'll both outlast me. There are plenty of modern equivalents, like the Turkish CZ and Springfield XD's that I've picked up in the past couple of months.
You can pay more for a handgun that's fancier or has more features that you like or whatever, but you don't have to pay more for something that works.
Thinking about it, it's largely an experience thing. Those of us who have owned and bought and sold a bunch of various handguns know what we're looking for. If you give one of our more experienced board members the quest of "Purchase a functional HD handgun for $350 OTD or less", they will immediately have some ideas. A completely inexperienced person would have to rely on luck or random YouTube reviews.
This was right around $250 OTD a couple of months ago (used, of course). Trigger and sights are great, shoots great, no malfunctions. I won't shoot it enough to wear it out. When I saw it on GB I already knew a whole lot about it, knew what to look for in the pictures, knew what to be careful of regarding the seller. A brand-new shooter would have just seen one more cheap polymer pistol. We all know that it's a fabulous choice compared to a SCCY or Hi Point or Jennings, but a random person wouldn't really know that.