I think a trade would be dependent on what the other person wants or needs.
For instance, I wouldn’t think a used FF Toby and a used Bertram would equal a used Alfie, but a BNIB FF Toby set and a BNIB Bertram might seal the deal on a used Alfie.
How about a Bnib American accent T’nA James for a used Alfie?…probably not, but maybe for a used one.
How about BNIB Monty for a used Alfie?…not in a million years, but if someone had a used one and wanted the other one used, I could see them being swapped.
Maybe something enticing and cash?
Either way whatever you’re trading for should be nearly equal in value to whatever it is that you’re offering.