The potions can also be made by shaman through the alchemy skill.
The level X potions cost about 43pp in vendor ingredients and requires a nodding blue lilly per attempt and yields 5 on a success. A highly skilled alchemist can make them for considerable less than the vendor price but the trivial 348.
Final price will relate to the alchemists actual skill and luck but you may find them cheaper in the bazaar than from the guy in PoK.