Some of the stuff you mention here isn't really what would be generally called a protein source, even if there is protein in it.
Eggs, Cottage Cheese and Tuna are all good protein sources. Eggs and cottage cheese being probably the most useful. Cottage cheese for example has whats referred to as 'slow release' protein which is Caseinates and is good for eating at night, but you can eat it any time you like.
Eggs, higher biological value than Cottage Cheese, also rich in fats, zinc and lots of other bits and pieces. Boiled eggs are 'transportable' which means, cook them and put them in your pocket and eat at will. Sausage is not a good protein source, I read lots of stuff about people eating sausage on here, and I say its shit and don't eat it.
Canned veg and beans are not very cool. Fresh veg is always better. Baked beans are ok when consumed with some milk or other complete protein source, a can gives you about 20g of protein and a lot of fibre. Cottage cheese and cold baked beans is a good bedtime meal if you like the sloppy taste. Chuck some olive oil in it and you have the perfect bedtime meal.
Milk is a good, but filtered and organic milks which have not been homogenized are better, but you pay more. I drink Gold Top jersey Milk which is richer in fats than whole milk and has mroe calories and isn't homogenized, just make sure its pasteurised, brucelosis and other pathogens are present in raw milk.
Stuff like sausage and similar isn't that cheap over here, unless you buy some really crap brand and they are full of quite nasty ingredients. The price of a packed of posh sausages would get you some lean mined beef or lamb anyway.
If you really are skint (broke) then buying skimmed milk powder in bulk from a cash and carry food wholesaler is the cheapest way to get some extra protein in your diet. Skim Milk is spray dried and although lots of heat is involved in the process the protein isn't actually much worse than regular milk. UHT Milk (sterilised) in the paper cartons that doesn't have to be refrigerated, strangely has a lower biological value than normal milk or skim milk powder.
I'd personally eat a clean diet high in fibre veg and decent protein sources, milk, eggs, cot cheese and buy some protein powder which would save you on food protein sources in the long run.