Hi,
The reason I'm not making high tier potions available easily is that I want players to brew them themselves. There's alchemy and herbs, so with a little bit of time spent farming while you have nothing else to do, you can make a nice stock of potions.
I saw a stack of 150 red herbs in the Auction House earlier, so with those and a few pollen, I'll be able to make heaps of healing potions now.
That said, I did notice that none of the NPCs sell mana potions, which is unfair towards mana-based classes. I'll have that fixed. :3