I bought one on here for 125.00 (3/8-10) and another with a silver ring for 140.00(5/16-14). That is what i payed, I may have got a deal or not not sure but it sounded good to me. These were OB-1
I guess everyone knows that predator has raised their prices on all of their shafts and i've seen some good deals on here for used predators in good shape. I was lucky enough to get an OB-1 with my cues matching ring work for a very good price a month or two ago.
Keep your eyes open and you'll come across a good deal if you aren't in a hurry. I would say $150 or less if the shaft is in very good condition isn't a bad buy compared to the retail prices for OB-1 and especially Predator.
I have OB-1 and Predator shafts and I think they both play very well. IMO the OB-1 has a softer hit than the Predator and they both do the job on reducing deflection. As far as Predator shafts go I prefer the 314-2 over the 314 from my experience since I own both types.