TheBlade Aftermarket shafts typically are in the $250-350 range. These are the same names of (some of) the shafts you find in the OEM drivers in the stores.
At the same time, you can 'customize' drivers and some of the offerings come with no upcharge. I'm guessing that means they are just cheaper shafts that fit within the original pricing, not 'made for', as different OEMs will offer the same shaft also with no upcharge.
I don't think anyone really knows any more. Unless the OEM has their name of the shaft, along with the mfgr.. Most used to say 'made for'. I don't see that any more.
I would just put 'pulled from XXX driver' in any ad. Let buyer determine. And...don't feel you are cheating yourself out of big bucks. Chances on that happening are nil.