Stock, I've come to learn, can make or break a lot of recipes. A risotto, for example, made with bad stock will largely taste like...bad stock. Buying stock/broth/whatever is expensive. A quart of stock can easily run a few dollars.
So - I decided to make my own. You should try it too. Veggie stock, because, as you'll come to know, I don't mess with meat.
What I did - collected scraps of veggies I cooked with in a gallon size zipper bag in the freezer. By the time the bag was full this included broccoli stalks, cabbage leaves, the woody parts of asparagus, brussels sprouts leaves, carrot peelings, portobello mushroom stems, onion cuttings, swiss chard stems, and probably a few other things in there. I put the bag in my largest cooking vessel - an 8 quart stockpot (wow, it actually got used for stock for the first time in its life!). I threw in a half head of garlic (whole, with as many of the outer papery layers removed as could be done in five seconds), half an onion I had in the fridge, some white button mushrooms, a handful of peppercorns, and some dried herbs (thyme, rosemary, parsley, basil, oregano - in decreasing order of amount of use). I added a few tablespoons of soy sauce because I read somewhere that that was good for flavor. Oh, and 5 very small bay leaves. And salt, lots of salt - I used a few large pinches of some pink jurassic sea salt I've had for a while. That's pretty much it, boiled that for an hour and a half, and done. Strain it, cool it, store it. I probably will freeze mine in small containers, about a cup or two each, for easy use. Some recommend freezing the stock in ice trays so you can just use as much or as little as you'd like at once. Yogurt containers are great for this, too. Discard/compost the leftover veggies.
Note that a lot of people will tell you to avoid using anything of the cabbage family in your stock - such as, well, cabbage, brussels sprouts, broccoli, cauliflower, etc. - because it will allegedly overpower the taste of the stock. The same goes for asparagus. I used them and am happy with my stock taste, but your mileage will vary.
Non-recipe for veggie stock:
Scraps of vegetables (enough to fit a 1 gallon bag)
Handful of peppercorns
A couple of shakes of favorite herbs
Enough water to almost fill the stockpot
Boil for 1-2 hours.
All my little containers of stock in the freezer. I made about 10 cups, but you can make more or less depending on how much water you start with and how long you boil it.