Numbers are extremely difficult to nail down. One thing we can do is to define what 952's exist.
The first guns were the 952 no-dash and these were exclusive to Banger Distributors. These are absolutely rare, reportedly only 200 were made. These have no grip safety/firing pin lock. They have a "billboard" large 952 on the left side of the slide. Price on these is too hard to accurately pin down. NIB/mint, untouched with all original package? Start at $3,000 and climb.
Next was the 952-1 "billboard." Pistol looks basically the same as the no-dash. All the markings on left side are laser etch, this model now has a grip safety that defeats the firing pin lock. I don't have production numbers but there are likely over a thousand and it would be my opinion that this particular one is the most plentiful of all 952's. NIB/mint, unfired with all original packaging? $2000 is bottom dollar, climbs from there. Solid used, with wear and missing original PC aluminum case? $1,500 to $2,000 is ballpark.
After that they made some visual changes and released another 952-1, this one no longer has laser etchings on the left side and has the more familiar stamping. This gun has no "billboard" 952 logo and may appear a little cleaner and less flashy. It is otherwise exactly the same functionally as the previous 952-1 Billboard. Again, no numbers but experience tells me that these are in shorter supply. The market doesn't appear to add any premium to them.
The last model was the stainless 952-2 and this also saw the introduction of the 6-inch long slide and 6-inch HEAVY long slide models. The 5-inch 952-2 is a gorgeous pistol and the slide contour is different than the earlier blued pistols. Price for a 5-inch, again, 100% package is definitely above the earlier 952-1. Figure $2600+ and beyond.
The 952-2 6-inch long slide models command serious money... "catastrophic" in the opinion of some folks. Any long slide 952-2 under $4000 is unheard of and the high water mark that I witnessed on Gunbroker is $6,525.
Beyond that are some rare 952-2 and 952-3 made exclusively for the European market, these occasionally show up in North America but for the purpose of this discussion almost cease to exist. The 952-3 is exactly the same as the 952-2 except it's chambered for the 9x21, a popular European substitute for the 9x19 in countries where "military calibers" are restricted. (Sheesh)
952's can obviously appear anywhere, including the buy/sell area here on our forum. However, here in the last 5 years, there is one place that is the uncontested king of the 952 marketplace: GunBroker, and if you think any other venue is close, you'd be mistaken.