Try growing bean sprouts in your kitchen. It is so easy and they are very nutritious. Not to mention cheap.
Get a jar, a rubber band and a little cheesecloth. Buy dry lentils in the supermarket. You aren't going to need a lot of lentils to get a whole lot of sprouts. I haven't done it with dry beans yet, but they are next on the list.
Then, put half an inch of lentils in the jar and fill it with water. Put the square of cheesecloth over the top of the jar and put the rubber band around it so the cloth is held to the top of the jar like a sieve.
Let it sit overnight. In the morning, drain the water out and then rinse the lentils and drain that water out. Repeat in the evening. Repeat each morning and evening until the sprouts have grown to edible length, about a few inches.
Isn't the idea that you can do this yourself for really, really cheap a fun one? If society collapses, you have a source of greens and fiber.