I once met some hippie-like people who fed themselves exclusively by dumpster diving. Not sure where they got their stuff, but they had a lot of high-end foods (cheese wheels, expensive meats, not-so-fresh produce, etc). They lived in busses, vans, RVs and stuff like that. They didn’t have jobs; not sure how they got money for things like clothes; odd-jobs I guess.

Less extreme “hacks”: Goodwill, or Ross/Marshalls if you’re feeling fancy. Ebay/Craigslist/Offer-up (need to be careful about getting ripped-off, and Ebay isn’t as cheap as it used to be). Buy, cook, and eat mostly cheap staples (rice, beans, pasta, etc). If eating meat, you can use it sparingly by cooking recipes that comprise mostly of cheap staples. Budget Bytes has decent recipes. Unfortunately, most people’s biggest expense is housing, and there aren’t many “hacks” for that. Maybe, get a work-from-home job and move to Wyoming or something