Protein is protein, again this is simple and doesn't matter where it comes from because your body deals with it. Yes its different to digest from a shake to a cow but its protein. Guys get too caught up in this 80%,85%,90% etc quality which is mentioned on protein shakes. It does not matter and I will find some links to that. I know all about Amino Acids, thats not my point here ... you have again misunderstood me and if you look back to my last post in this thread I even say the body deals with different sources in how it feels necessarily.
This is a good topic because we can save tons of money by keeping it simple, such as below which is a simple protein shake from Arthur Jones ... he knew more about this than you'll ever do mate - Konstantin.
This will make 2/3 servings and you need as follows
1) 4 raw eggs
2) One half cup of soy powder (This can be skipped later on)
3) One and one half cups of powdered milk (Non-fat)
4) Enogh chocolate powder to give suitable taste
5) Enough skimmed milk to bring the mixture to a proper liquid
Mix the above in a blender or shaker. You consume one in morning, after workout and before retiring for the night.
You can substitute the Soy Powder for one half cup of milk powder, doesn't matter.
I have used baby powdered milk instead of milk powder if I can get it cheaper, if you use that use the one next up from new borns milk as it has more protein to it. That stuff is also closely to match breast milk. If you can find cheap Colostrum which is from New Zealand mostly and sourced from mother cows who are needing to feed young calves than use that. Full of good stuff.
This if all sourced cheaply is just as good like any top brand and you know what your putting in. In fact you could add other tit-bits if you like such as after a workout throwing in some carbs like Dextrose into the mix which is cheap as chips proven carbs. I'll get some more recipes on here especially from Vince Gironda because his were pretty exotic at times, way ahead of his era.
Eggs and Cows milk are very high grade proteins, that and also raw liver from bovine sources. I use Desiccated liver which is more potent than raw liver, I cant stomach cooked liver or liver for that matter but that is a fine way to get it into you and full of protein amino acids and b vitamins, plus very easily taken by the body unlike some proteins which aren't as easy for the body to take the goodness from.
If you can stick with natural type protein sources.