1. Lentils Legumes in general are going to be a go-to source for cheap nutrients, and lentils are a particularly good example of what this food has to offer. A 4-ounce serving of this inexpensive legume provides almost all of the folate (a.k.a. vitamin B9) our bodies need in a day -- 90 percent of the recommended daily allowance. Folate helps our bodies form red blood cells and break down proteins, and is essential for carrying out the most basic cellular operations. Lentils also boast about 25 percent of the RDA for thiamin, or vitamin B1; this one helps our bodies break down carbohydrates for their stored energy. More huge benefits? Lentils are an excellent source of dietary fiber, manganese, iron, vegetarian protein and low-glycemic-index carbohydrates. They're a staple in Indian cuisine and lend themselves well to all sorts of soups, stews, side dishes and even casseroles. 2. Eggs Versatile and super-easy to prepare, eggs make a great low-cost, vitamin-rich ingredient. At breakfast, lunch or dinner, a single egg offers a nice supply of the B vitamins 2, 12 and 5 (14 percent, 10 percent and 8 percent of RDA, respectively), all of which play roles in extracting energy from food and forming essential blood structures. You'll also be consuming about 7 percent of your vitamin D for the day. If you buy vitamin-D-enriched eggs, which are common these days but do often cost a bit more, that number goes way up. Egg-based dishes like omelets and quiches, which contain about two eggs per serving, are especially effective meals for meeting your daily allowance of B vitamins. But keep in mind that egg-white-only dishes don't count: These vitamins are in the yolk. Speaking of B vitamins, eggs also supply a substantial amount of choline. Choline is not a vitamin in the true sense but behaves similarly to B vitamins (and is often considered an honorary member of that family), facilitating all sorts of chemical reactions in the body. This one appears to be especially important to the nervous system. 3. Spinach If you love spinach, you're in luck: It's one of the most vitamin-rich foods in the produce section, and at less than 20 cents per serving, it's easy to work into your food budget. The laundry list of vitamins found in good supply in spinach includes: Vitamin K: 1,100 percent Vitamin A: 380 percent Vitamin B9: 65 percent Vitamin C: 30 percent Vitamin B2: 25 percent Vitamin B6: 23 percent Vitamin E: 20 percent Vitamin B1: 12 percent Of the vitamins in spinach, you're getting even more than you need of K, which is necessary for blood to clot and for maintaining healthy bones, and A, which helps your eyes function properly, among other benefits. With one-third of the iron you need, too, and calcium, protein, and fiber, you could almost live on this bright-green, leafy vegetable. Remember that a serving is one cup cooked; if you're eating it raw, double or triple that cup for a good dose of your daily vitamins. 4. Oranges Let's face it, fruit isn't cheap these days. And while some of the more expensive kinds, like raspberries and blueberries, are also some of the most nutrient-rich, you can find plenty of good stuff in the more affordable varieties, too. Take the sweet, juicy orange. One large orange (or a small glass of its juice) has more than 100 percent of the vitamin C you need for the day – necessary for collagen formation, healthy teeth and bones and iron absorption (and while it hasn't yet been proven, it may also help to eliminate dangerous "free radicals"), which makes for a very well-spent 40 cents. That orange also provides a decent amount of B9 (folate, 10 percent) and small amounts of vitamins B1 and A. 5. Sweet Potatoes They're not just for Thanksgiving! The sweet potato is a healthier version of the ever-present white potato, and you can do with it pretty much anything you can with its less-colorful buddy: Bake it, mash it, cube it into stews or cut it into fries. In one medium-size sweet potato, you're getting more than two-and-a-half times your daily supply of vitamin A (actually carotenoids, which your body turns into vitamin A), which helps maintain eye health; almost a third of your vitamin C, which your body uses to form collagen; and more than a tenth of your vitamin B6, which facilitates chemical reactions throughout the body (especially involving proteins) and helps to form neurotransmitters. Source
