My non-Mustachian coworkers spend an average of $10/day for lunch on over priced sandwiches at local places near my downtown Boston law firm. (They typically supplement this with daily 3 pm Starbucks runs for overpriced lattes). I recently made and froze 38 burritos. using flour tortillas (filled with homemade refried pinto beans (made from dried beans, bought in bulk), rice (bought in bulk, seasoned with cumin, chili powder and dried oregano), caramelized onions, and roasted bell peppers) for a total cost of 60 cents/burrito. They taste great reheated in the toaster oven at work, and are now allowing my fiancee and I to eat a healthy lunch for 60 cents/day, $6/week for both of us. If we're feeling extra fancy, we add a slice or two of avocado on top.
Assuming that we were also indulging on a $10/day lunch habit, that means that we're now saving $94/week, $376/month, which is going straight into our 7% student loans.
BOOM.