I would say somewhere around 20 a cue. More depending on what wood is underneath the gunk and junk.There's still quite a bit of these out there and I find them pretty regularly at at junk shops, estate and garage sales. The key here will be how thick they are. I've found more than a few TB's that were straight but not thick enough to get a full butt out of them.
If you can get a full butt out of them I'd value them a bit higher.