Cost: $2.99 per two-pound bag
Benefit: This bulb boasts far-reaching health benefits, including immunity-boosting compounds that can help prevent everything from the common cold to cancer. Onions are also rich in quercetin, a flavonoid shown to keep your blood healthy. It's also a must-have for natural allergy prevention. Tip: Store your onions somewhere cool and dry, such as a dark cabinet or unused closet, and that two-pound bag will last for months.
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