I am looking to buy a beacon..Pm me with the price and info. I am also looking to buy Wither Skeleton and any other kinds of heads...Also Pm me the price and info on that. Happy Wither Hunting!!
You can't get creeper heads (or another sort apart from wither skeleton) currently, they're creative only.
Could you link to wherever you got that information from? Because I just searched for it everywhere. The wiki very clearly states there is no legitimate to receive mob heads other than the wither Skull. If there is indeed a way to do this with the anvil, please provide proof.