Soylent is $2.69 / 400 cal and vegan.

To get the same macro ratios you don't need the corn meal, the shakes have plenty of carbs, you can do 1 shake @ $3.33 + 15g coconut oil @ $0.55 + a few cents for the multivitamin = ~$4.00 / 400 cal.

(You may still want the cornmeal for fibers and slower carbs, since the carbs in the shake are all from milk and cane sugar.)

So it's more expensive, requires preparation, is not vegan, and the glycemic load is probably worse. Beautiful.