I have plenty of condiments and supplementary food, like liver, eggs, corned beef, butter, burro bananas, and plantains, so it's not as super boring as it sounds, but I do pretty much eat the same things most days.
I would guess $120 on average. I'm 5'8 and weigh 140-145lbs. I'm extremely inactive most days, though, except for a heavy weight lifting session once a week just to maintain muscle mass, but I've been very inconsistent with it. Lately I literally don't even get out of bed most days except for necessities. According to this 30 mins of walking a day at a 3mph pace burns 120 calories for a 150lb person:
http://www.fitnessforweightloss.com/...-burn-walking/
So I would add maybe $15 more a month for a person with this much average activity. Shoot for $150 a month without any eating out.