The Daily Dinar

Zenhabits has the answer:

I submit that I save at least $3,000 a year (and possibly more). How? Well, my co-workers often spend $10-15 per meal on lunch. A brown-bagged lunch costs between $1-3. If you save $11-12 every weekday, for 52 weeks of the year, you get about $3,000. Now, if you also eat out a lot for dinner, eating in for dinner would save you just as much. And if you eat out on weekends, your total amount saved by cooking for yourself could reach $7,500 or more.

Attaining wealth isn’t always a question of earning more, it’s also a matter of spending less.  Make Your Nut makes a similar point.