Of course its cheaper and easier to make ur potions if u r collecting the ingredients already while ur questing etc,
The money u make does justify the small investment of going ther + getting the stuff,
I think people get too greedy at the AH, thats y they don't sell that much, i am always reasonably priced and sell on average 8 out of evry 10 items that i list,
There's not many people who want 2 pay 10 gold + per potion, be sensible now!!!
if u didn't have herbalism or an alt. that pikked herbs it would get incredibly expensive 2 get all ur skill points buying stuff @ the AH!!!!