In the average grocery store, you will find a surprising variety of dried beans. A pound of dried beans cost between a dollar and two dollars, though that may vary regionally. A pound of dried beans makes about 12 servings or 6 cups of cooked beans. That works out to less than 20 cents a serving.
These are the types of beans I found in my store:
Remember that you can also purchase beans in bulk at many mainstream grocery stores. You may find an even larger selection of bulk beans at your natural food store. And of course, there are lots of ways to purchase beans online. See the resources section of this website to find several online purveyors of beans!
The different bean varieties all have different tastes and textures. Garbanzo beans have a firm texture and a great nutty flavor. They create a delicious broth that is a great background for soups. They are wonderful thrown into a green salad. Black beans are smoother; more velvety. Pureed in the blender they turn into the delicious, and ubiquitous, black bean soup. But they are also great tossed in a salad or rolled in a burrito.
We may think of certain beans in certain contexts (i.e. pinto beans/TexMex, cannelini beans/Italian). But there is no need to be limited by that. Experiment with the bean varieties and the flavorings that you add. See what happens.