5. Onions, Leeks, Shallots, Garlic
Hardly anything bothers the onion family. Just keep these watered, and they’re all among the cheapest, easiest-to-grow crops.
Onions aren’t that expensive but at least are good keepers and versatile. Despite their ease of growth, leeks, shallots, and garlic fetch a good price at the store, making them winners in any cost-benefit analysis.