I didn't read through whole thing day by day but on day 1 he uses his food money to purchase non food items because they give him coupons worth more than what he had to pay for them in cash: http://www.grocerycouponguide.com/articles/eating-well-on-1-...
One wonders if he should have included gas burnt driving to all the places which had stuff on sale, and I definitely support all of the opportunity cost comments.
On one hand it's not the most economical use of your time if you can sell the time you spend on doing this. On the other hand if you can save 5$ by sacrificing one minute you can get pretty decent hourly rate on your effort.
Also this guy seems to be having a lot of fun gaming 'the system' and blogging about it.
