I am developing a selection of food stamp friendly Soylent recipes. I am currently testing four recipes. So far, every ingredient used can be bought on food stamps, at least in Idaho (I know, because I did it). I have also taken pains to choose ingredients that should be available in at least most places in the U.S. This is a completely open source project, so the recipes along with all relevant information will be released freely.
My cheapest recipe so far is $1.38 a meal, at local Idaho prices, with almost everything at regular retail pricing, except 3 spices/herbs bought in bulk. (In other words, there may be room for improvement.)
I am also considering making a self published (via lulu.com) recipe book, if there is enough interest to justify the effort.
I am posting information regarding this on my blog. The introduction to this topic is at: http://makeshifttechnology.blogspot.com/2013/08/soylent-introduction.html This is where I will be posting my recipes and other information as well. I plan to post all of my documentation and research references sometime this week (Friday, probably), and I plan to post the four recipes I am currently testing by Saturday.