Inspired by @hillarykerr's worth-it list for beauty. The most important rule, of course, is that what tastes good IS good. Eat (and buy) what makes you happy. But in my decade-ish of being a professional food writer, these are the best ingredients on which to drop extra cash. (I'm not talking ethics here, just quality/deliciousness.)
  1. Fancy dried pasta
    A $6 pound of fancy penne actually *is* 6x better than a dollar box of De Cecco. Usually these come in bags rather than boxes, and are on lower shelves. (I'm not talking about bags of gluten-free whatever; I mean the stuff that's imported from Italy. Even the Rao's stuff, branded after the NY restaurant, is terrific.)
  2. Tea, especially green teas and herbal teas
    Tea is a commodity good, which means there's almost no differentiation between a plain tea bag from Lipton and a plain tea bag from some annoying White Lady Namaste brand. But you do pay for quality when it comes to blends and flavors — especially fruit and floral infusions, which are much cheaper when fake. Jasmine is an expensive flower, it should be an expensive tea.
  3. Butter
    It's not unreasonable to pay $12-15 for a pound of really, really good, local-artisanal-whatever butter to serve with bread at a dinner party. Think of it like a cheese. Lean in to yr butter. For everyday use, high-fat European-style butters like Plugra and Kerrygold are available at every grocery store. They're significantly more flavorful (which means a small amount goes a long way, and that baked goods taste better), and store in the fridge/freezer beautifully.
  4. Milk
    Small-farm milk tastes like actual milk — sweet, creamy, grassy. Like fancy butter it can be mind-bogglingly expensive but the flavor is extraordinary, and it elevates even a bowl of cereal. Bonus, usually comes in super cute glass milk bottles
  5. Grass-fed or grass-finished steaks
    It tastes so, so much better than corn-fed. Especially if you're into tender cuts like filet mignon or super-flavorful cuts like bone-in ribeye.
  6. Cane-sugar sodas (for cooking)
    If you're making something like a Coca-Cola ham or Dr Pepper pulled pork, spring for cane sugar variants instead of HFCS — dissolved cane sugar caramelizes differently (better!) than corn syrup, and you'll get the depth of flavor these recipes (which largely predate HCFS) are supposed to have.
  7. Fancy salt
    Different colors and shapes of salt DO taste different, and affect your eating experience in different ways. Flaky finishing salt like Maldon adds a huge impact to dishes (don't cook with it - just sprinkle a pinch on at the end so it looks pretty), gray salt really does taste minerally, etc. You don't need a full library of salts, but one or two fancy ones are great pantry additions. (I'm not talking about flavored salts, btw. Skip those, mostly, except real-truffle truffle salt.)
  8. Any fruit or vegetable you've never seen before
    Mugwort? Purple carrots? Garlic scapes? Jackfruit? Buy it immediately. The world is full of way more than the five vegetables and six fruits kids learn about in name-that-color picture books. Support biodiversity, for sure, but also the weird stuff is usually terrific tasting.
  9. Fair-trade superfoods
    Ok I know I said no ethics but: Quinoa has been a staple ingredient in Peru and Bolivia for literally ever. Because of American demand, the price has skyrocketed to the point where the families who farm it can no longer afford to eat it, so they're eating processed, packaged food instead. The irony is phenomenal. You can afford an extra $5 or $10 to save the health of the ppl who grow your high-protein non-carb AND prevent the destruction of a thousand-year-old food culture, right?
  10. Eggs
    I always have two types on hand: cheap large ones, for baking and recipe testing, and fancy expensive local ones, for eating straight, usually scrambled or as eggs in a basket. They are so much sweeter and more flavorful and pretty.
    Suggested by @mollyyeh