You can try put in your npc
elseif msgcontains(msg, 'health potion') then
buy(cid,7618,getCount(msg),50)
elseif msgcontains(msg, 'great health potion') then
buy(cid,7591,getCount(msg),120)
elseif msgcontains(msg, 'strong health potion') then
buy(cid,7588,getCount(msg),220)...