I know that you dev's are having trouble coming up with a reasonable solution for us specifying what we want to purchase, but to be honest, I don't really care how it works, or how crappy it is, just so long as we can do it.
For my ten cents, how about you use the recipe's that the character currently has access to for a list of things that can be placed in the buy slot, and then just a ticker for quality.
I don't care about items that can be crafted from different base materials, a scythe is a scythe whether it's made from bronze wrought or steel.
If you do something imperfect and have to change it later then that's OK too, just try to think of it as an experiment
