If it's liquids that you're buying in heaps, I'd just reassure him that it's kind of like buying a carton of smokes instead of a single pack, and that you'd end up spending the same amount of money anyway. Otherwise I'd just be like, "I need to find out what works best for me, but don't worry, I can later sell all of the equipment I don't need and get some money back, or trade it for liquids and stuff I will eventually need more of."