I dont dare to put price tag to it but here is my view on its usefulness.
Despite it having great MF amount, it would still be MF-swap only option for me since it lacks any primary stats, ie.DEX/STR/INT & VIT. That devaluates it in my eyes a lot.
Nonetheless it is very nice piece of gear and should bring you fair amount of gold. Mind you plain 35% MF on amulet is commonly going for around 100k gold on EU AH. Now find what is the price of CHD + CHC amulet and add premium for extra MF to get the price.