You can find nutritional yeast in most grocery stores, either in the bulk bins or the spice section. You'll get the best deal from the bulk bin section, however Trader Joe's also sells bags of it for pretty cheap. And incase you're worried you'll only use it once, there are myriad possibilities for nutritional yeast. Sprinkle it over popcorn, roasted veggies, or pizza for a savory boost, or use it in dairy-free mac and cheese.