78 rpm & related cds

To answer part of your question country blues 78's can go for low hundreds to low thousands (of $). I don't know what Chicago blues 78's go for. It must be fun, but it's a well trod field, if you know what I mean.

See Ghost World or Crumb to see the collectors who have gone before you.

Gregg

The main thing to remember with 78s is the groove size is different from 45s & 33s so requires a cartridge with a 78-sized stylus. While 78s will play with a regular cartridge needle, it tends to ride the bottom of the 78 groove and is far noisier than it should be.

Some modern cartridges with removable styli have a 78 needle available, so one cartridge can do double-duty if your turntable supports the 78 speed.

I took a chance and bought a cheap Sylvania ceramic cartridge idler drive at a yard sale for $10 just for the purpose of playing old 78s to record to digital. THis was a home run. Th old 78s from the 1920s-1940s sound great on my modern system and are a lot of fun to listen to. Of course lots of surface noise and limited overall dynamic range and frequency response is a big part of the 78 recording game. The microdynamics of these old 78s are their most interesting audio feature. I do not recommend investing in anything fancy for these, but strongly encourage those motivated who have never attempted to bring old 78s into their modern audio fold to give it a try.