What's the market these days for NOS 70's/80's cartridges and/or tonearms?


I've noticed the market has seemed to change with respect to a lot of vintage gear.  However, it used to be that certain vintage gear, especially if NOS, such as the Pickering, Shure, Stanton cart's and perhaps SME tonearms never went down.  I'm getting some indication that this may no longer be the case?   Yet, recent searches hasn't turned up any useful data.  Any ideas on market or sources to determine the market?
nolojunko
@mijostyn  No, I did not buy all of them yet, but learned which of them can be ignored. 
I have a NOS Shure V15-mk5mr in original box plus a NIB Jico replacement stylus. Wonder what these will be worth two decades from now? So far I have held off from using this V15! I have plenty of other cartridges on hand. Using the NOS Shure can only reduce its future monetary. value.
Original Blue Note jazz LPs now sell for hundreds! I can't afford those - and wouldn't pay those prices anyway! Anybody want to bid on my Andy Warhol banana sticker (intact) Velvet Underground LP. Record mint - looks never played. Cover (version 3) is EX (showing signs of minor aging). There are some now on Discogs listed at over $1K not as nice as mine!
Speaking of tonearms: I have a NIB Mayware Formula 4. Back in the Days of Yore (1977) I had the Australian JH copy  mounted on the Ariston RDII Superior TT with a Microacoustic 2002 electret cartridge. This was a particularly nice sounding set up!