That per-meal cost, averaged out across each week, is under the standard version of the "spring menu," which utilizes more fresh produce and seasonal ingredients. Go the "green" route, buying local and organic food, and your cart cost comes to about $1.99 per meal; switch back to the "winter menu," and it gets cheaper. All those prices are, as the site's creator points out, less than the individual food stamp allowance in many states.
The menu, devised by a former IBM engineer, is largely vegetarian, though it contains some surprisingly cheap but appealing items: spring onion and mustard green pizza, green egg scrambles, and noodles in spicy peanut sauce, as examples. Some menu days won't really surprise anyone who's made it through college on the cheap, as it leans on beans, peas, and rice fairly regularly. But the day-by-day planning is so comprehensive, and the options so thorough, that those looking to eat healthier, cheaper, or start out on a flexitarian diet will find Cook for Good's offerings a pretty great free resource.
Head over to the site to check out the winter, spring, and supplemental menus, as well as read more about the project. Update: Looks like Cook For Good's a little overwhelmed this morning; check back later for a better chance at access.