Oh no, it's much better than that.

Google suggests it's 8g per 100g, which on paper doesn't sound great but a package over here is around 2 bucks for 16oz, roughly 450g. Being conservative we could say 50 cents for 100g.

8, 16, 24, 32 puts us a little under 2 bucks.

That said, tofu is 5 servings of 70cal; the 100g isn't all calories. I'm guessing water? In any case, that eats into your cost effectiveness, putting it closer to the center than near the legumes where it really should be.

Your mileage may vary though. Nuts are great, but peanuts only pull ahead because of how insanely cheap they can be. They're much fattier. Tofus great, though, if you prepare it as intended and not as some meat substitute like many Americans tend to do.