Idea:
New merchants that do different things!!
More information:
Portable Merchant: take it anywhere!!
EVIL Merchant: replace your enemies merchnat with an evil merhcant for 1 Minute has RED eyes of EvIL
Sell Merchant: basicallt sell stuff for less than you got it for tho
Cursed Merchant!!: Sells you stuff cheaper but with curses and sometimes the objects are cursed!!
Merhcant Merchant Upgrade: add Merhcant Merchant next to your other Normal Merhcant and so begins the CHAOS!!
I can think of more but not right now