Where do you get the potions in the first place. I know about the refill vendor but have not seen them for sell. I had one power potion on a toon I got to level 9 but to be honest I do not remember where I got it. I am thinking a quest reward.
You get potions as you complete quests throughout the game. You get three potion bottles in total and they can be refilled by playing the mini-games as well as buying the refills from the lady in the Fairgrounds.
You get a potion bottle by completing Merle's quest. When you have on potion bottle (located by the side of your health and mana) then you can play games to earn mana. The best game for me is Dueling Diego.Short and easy