With the way nixie prices have been going, Its really hard to price things right now. Some have been going sky high. Some have gone nowhere. I just followed a couple of dekatron auctions. A GC10/4B and a 6802, rom the same seller. One went for $10, the other for $5. That's pretty sad, because I have quite a few of each.
The ZM1050 is a pixie, but not a real pixie, which were made by Burroughs. The ZM1050 was made by Philips (Amperex/Mullard/Valvo). It was designed to work with low voltage transistors, and can also be rigged as a counter, with a little more circuitry than needed by a dekatron.
I was given one by Westdave a few years ago, and they ran about $35 each, at that time. I guess they're more now. How much more ??? Hopefully, it didn't go in the dekatron direction. I don't think so, on account, I only own one.