No idea, that would depends on what you eat. Obviously if you went for totally organic fruit & veg, and/or lots of processed faux meat products, then it could be quite expensive. But obviously you don't have to have those. So it can be done fairly inexpensivley.
^^good words. Basically if you simply eat food, and not processed food, you are economically better off. if you sprout or garden, even cheaper.
Beans are seriously cheap and filling. Im not a vegetarian but ive recently incorporated beans into my menu big time and for $2 you can make enough for dinner and lunch the next day. Add some tomatoes, potatoes, garlic and parsley which cost next to nothing and you can come up with some really flavorful stuff.
it depends on how smart you are when you shop. the way I eat, it's much cheaper. it is probably about the same if you eat those fake meat crap foods because those can be expensive...but i can eat for pretty cheap, probably cheaper than if i bought omni food