Anecdote: Two person household experimenting with meal plans (breakfast+dinner with leftovers for lunch) and our groceries cost about $400/mo. Personally, that number seems very high to me, but it could go down as we prioritize cost over following Recipes As Written. Cost was stable around $300/mo before, but with less varied meals.

Those two numbers translate into $50/person/week and $37.5/person/week.

I wanted to try out Soylent for a breakfast replacement, but was also turned off by the price. Edit: Also the delay! Wow, 4-5 months