So under the heading of proteins, I will deal with the sorts of meat, meat replacements and dairy products that should be in your stocks, so that not only you are fed, but you have enough variety to stave off boredom, all the while keeping with the budget.
So first off, animal flesh.
Keep in mind that the more work a butcher has put into the carcass, the higher the price tag, influenced with the market's offer-and-demand philter. If you want to maximize your budget, accept that having to deal with bones might well be on the table; you'll also have to deal with fattier cuts, because trimming costs more money. Now bones and fat are not waste, far from it. Bones enhance the flavor of stock and sauce, and fat is concentrated nutrition and makes meat more tender. Get yourself some knife skills and you can do the trimming job yourself, re-purposing the trimmings for your own benefit. Tougher cuts also become a factor, but that means learning slow-cooking methods and far more flavorful cuts. Seriously, tenderloin is boring as all hell.
So, by beast, the cuts:
|Here's looking at you, kid.|
|Can you find Waldo?|
-Lamb and goat:
|They forgot to tell you how delicious Lamb Chop was.|
|You know, the other white meat.|
|They see them hanging, they be hating.|
Having some dried cured sausages around is always a good idea, since that they are versatile and have a longer shelf life than fresh sausages. Of my favorites I would got for Spanish chorizo and Romanian kabanos. They can be eaten as-is, or cubed and added to bean dishes for flavor and meat content. Buying bacon in chunks rather than slices is also a good idea, as it leaves you with a greater range of use than the traditional sliced kinds. If there is a deli shop in your area, look or ask for the butt-ends of cured hams, like prosciutto. They may well have those pieces on sale as a chunk, as they become too difficult to put on the slicer and they want to maximize their revenue. Treat like bacon slabs as for their use in cooking.
I would certainly suggest that you mix and match, vary your stocks and keep it flexible, but my rough list of things that should be in supply are a boiling chicken, some lamb or pork shoulder, a pair of chorizo, a slab of smoked bacon and a selection of good sausages. Once that you know how to handle them, its pretty amazing the variety of dishes you can come up with that variety, and I haven't even dealt with dairy and other options yet...