While some people like to only use homemade broth, I think that high-quality store-bought broth works great and is very convenient. Broth is available in either cans or aseptic packages. While I like the aseptically packaged broth better because it seems to have a longer shelf life when stored in the refrigerator than the cans of broth, aseptic packaging (poly-coated paperboard) is still more difficult to recycle than cans. However, the number of MCDB (Milk Carton and Drink Box) recycling facilities that handle aseptic packaging is growing fairly rapidly in the United States, and I believe this is a trend that will continue.
If possible, look for broth that is organic and doesn't contain preservatives or artificial additives. I also like using low-sodium versions as this allows you to adjust the salt profile in the recipe. Regarding storage, once opened the broth can be stored in the refrigerator; I suggest following the directions on the package. You can also pour the broth into ice cube trays and store in the freezer; the broth will last longer and you can have a convenient way to use it in the future.
If you'd like to make homemade vegetable broth, here's a recipe:
Optional ingredients: 4-5 cloves garlic (that have been pressed with the flat side of a knife), ½ tsp sea salt, ½ cup tomato sauce (for tangy broth), any stems you have left over from cooking vegetables (e.g., kale, collards, chard, etc.)
If you want to make chicken broth, add two to three pounds of chicken (cut up into serving pieces) at the beginning of the recipe. Increase the cooking time to two hours.