What are older working Sheridan c02 pistols going for now a days ?

Crickets? I have a couple also.

I’ve seen these things go for $350-400 on auction sites to $125-175 on craigs list and forums. Don’t know!

Any estimate today is probably out of date.
I just read that a FWB124 sold on eBay for >$1000, which is crazy.

Lots of powder burners are migrating to airguns due to ammo shortage.

Hard to say. Collectors, being collectors, might pay almost anything to complete their slams.

For the rest of us, the Crosman 2240 is an easy choice at about $60, before you start looking at upgraded parts. I bought the steel receiver and rail. Shoots as good as I can, for less than $150, if you don’t count the optics, which are in a constant state of flux.