IMO stipulating that those who want to eat should cook or clean makes sense. Yes, we do.
Veggies are no problem in summer.
We have some from the garden but more donated from the shares of those who are members of some of the local CSA farms, which are generally in excess of the families' needs. Organic adds a little bit to the cost. You can also substitute stuff like textured soy protein for hamburger and have a pretty inexpensive meal.