Have you tried cooking dry beans? It is really easy and cheaper than canned. I bring them to a boil, can the water and then put them in the oven. They last for days in the fridge.
The pressure cooker I bought: Hawkins 5L classic: http://www.hawkinscookers.com/1.1.1.hawkinsclassic.asp
Here in NYC at least, foods like beans, lentils, rice, spices, etc. are much cheaper when bought in Indian food stores (where they're everyday staples sold in large packages) rather than in regular supermarkets (where they're sold in much smaller packages).
There are similarly good deals to be found in Chinese and other ethnic grocery stores.
Beans like most seeds contain specific toxins that are aimed directly at mammals to prevent them from being eaten. This is why you can't eat just about any seed in quantity without processing it; they don't want to be eaten and conduct chemical warfare to prevent it.
Even once processed you are still getting a huge amount of toxins, just not enough to be sick enough to notice. I don't know why anyone eats beans, ignorance I guess.
Beans are also loaded with carbohydrates, peeled potatoes are a much safer source of starch if you just want to load up on starch.
Fresh beans though are definitely great, and with homegrown ones you can cook the pods too.
Dried black beans, $1 - $2/pound.
Can 15oz black beans containing 1 1/3 cup drained beans, about $2.
2 cups dried beans yields 5-6 cups cooked drained beans.
1 pound dried beans = 2 cups dried beans.
Rinsed, un-presoaked black beans cooking time: 25 minutes, after maybe 5-6 minutes of bringing it to boil and reaching pressure level.
Cooking time for can of beans: 5 minutes.
Dry beans really do need a soak. When you bring a pot full of cold water legumes to a boil (assuming you haven't presoaked over night in cold water) turn them off the heat and let them sit for 1-2 hours. Even though they are off of direct heat, the cooking time is similar to if you had left them boiling that whole time.