Found Texas Prepper, a man after my own heart. In this series, he builds out a small greenhouse using cattle panels, fence staples and plastic wrap. I watched all three of his videos (the prototype, his second one, and the final). I am including the best video here, but will provide links to the others below so you can see the evolution.
A DIY video on building a portable, inexpensive greenhouse that's VERY easy to build, and will cost you about 150 bucks (depending on materials in your area) and a few hours of your time. It's a design I call "TexasPrepper's Greenhouse". I did an earlier video showing the finished greenhouse, but this one details the construction.