I'd say it matters a lot where you live and how you live. It's easy to live on far less than 100$/person_week in NY (or Tokyo, or Paris) with a tiny fridge and single burner stove, when you eat out 15 meals a week, or when you work at Google, or when you live in a rural area where prices are lower. But if you're urban, without a car, buying from tiny expensive bodegas, with growing kids, and can't afford to eat out, your bills will be significantly higher... Dog forbid you're buying pre-packaged or snack foods 'cuz it's easier than listening to home-alone teenagers complain.
Make 3 days worth of rice in the fridge. Freeze small batches of stews/soups/vegetables. Scramble eggs with different ingredients. Different spices/sauces. Eat fresh stuff on shopping days.
We could go for education, but many people do not take education even when offered for free.