Navel Oranges (about $0.84 each)
Seedless and sweet, navel oranges have a belly button-like protuberance on the blossom end. (In case you’re wondering, it’s actually a second small orange.) These citrus fruits are an excellent source of potassium, vitamin C, and folate, which can help prevent neural-tube birth defects. Look for the best ones from mid-fall to early summer.