Have seen spent grain for sale on Market Place and have considered it based on the cheap price for amount you get. I talked with a produce guy years ago about getting expired produce for my compost pile. He told me they couldn't give it away anymore because the pig farmer that used to take it got a batch with broken glass in it and tried to sue the store. I my area, everyone want's to make a buck off of anything that is scrap rather than giving it away.Spent grain is readily available from local breweries. Combined with scraps from restaurants and grocery stores, you are set