north east of the big fountain in pontera is a building inside npc's sell weapons/armors and the potion books for alchys(im asumeing u want those)theyre kinda expensive but u just need to have it in youre inventory to make the stuffys and it wont dissapear,also to buy stuffys u might need for potions the alchemist shop is just a bit right outside the building hope i helped~nyo^^