I've doing the diet for about 2 weeks. Exploring different vegan protein sources. Tofu, tempeh and Seiten
Nuts, seeds, beans and other legumes.
Oatmeal, granola, sprouted bread, hummus and pita and rice and beans, peas, chickpeas, edamame, etc.
I basically just have to make a big pot of rice (or quinoa) and beans and eat that all day to save the most money.
Otherwise making your own tofu or seitan, would be more cost effective.
I kinda caved and brought a bunch of veggie burgers that contain egg protein, so they're vegetarian but not vegan.