Now that it appears that there is a much smaller offering of 500 series stuff on eBay, where do people get stuff now?

There hasn't been a 1S2 listed in years AFAICT. The single 1S1 that's on now has been re-listed several times at 280$.

Spectrum analyzer plugins, 1A5, test units, Type O, etc

So how does one ascertain the value? Where to get one? I mean there's a Type O for 200$. Who would buy that?