There are two ways to buy beans: canned or dry
Canned beans are convenient. Just open the can. Most are high in sodium, but you can get low sodium or no sodium beans. If you have a problem with sodium like high blood pressure buy the low or no sodium.
Canned beans can be heated stove top or microwave.
Environmental note: One can a week is 52 cans of trash per year.
Two a week is 154 cans a year. More per week are more trash per year.
Cans also absorb raw materials in the making.
Dried beans may require a period of soaking and all require cooking. Lentils, Split Peas, Mung beans and Adzuki beans can be cooked without soaking first. The rest require soaking and/or long periods of cooking time. More soaking means less gas (farting).
Environmental note: Cooking beans produces heat. This is good if its cold outside. It warms the house. If it is warm or hot outside, the heat will not be appreciated and may require air conditioning to remove it. Cooking time is shortened by soaking first, using a lid on the pot always and shorted by half or more using a pressure cooker.
Here is a guide for cooking beans from the NY Times.