Is Skim Milk powder a good option for protein?

I hate to say it, but how long is a piece of string.  Without knowing your type of training, calorie and protein requirement I can't really say.  Similarly adding skim milk to milk and protein powder is hard to answer as I don't know what brand of powder you are using or how much milk you are adding all this to.

So, let's take a general approach to this one.

Most protein powders will give you 20-30g of protein per serve.  A serve is typically 3 small scoops or 1 big one or 3 tablespoons.  So the first thing to ask is how many serves can I get from my tub of protein?  The brand I use gives me 33 serves, and at $55 a tub that's $1.67 per serve.  An espresso is around $3.50 - $5, so even if I give up 1 espresso per day, that's 1 serve of protein I can afford - and chances are I'll use this serve around my workout and leave the other sources of proteins for other meals.

Let's say I use this protein twice a day.  That's $27.50 a week, let me check my budget, what am I spending $27.50 a week on that's not necessary.

I promote eating free range eggs, but for the sake of budget, one tray of non free range eggs may cost you around $5.99, which is 20c an egg.  One egg will give you around 5.5g of protein, so 2 eggs at 11g of protein could make up 1/3 of your protein requirement.  Now my 33 serves of protein could last approx 44 serves if I add a couple of eggs...and we don't need to add any extra fats.  Now, my $55 tub of protein could cost me $18 for a week.

And so on...

8 Tablespoons of skim milk powder will give you close to 30g of protein, but also 33g of carbs so if you are adding this to milk (which also has carbs) and maybe a banana you need to make sure you're not doubling up on your carb intake.

Now depending on your training, you might only want 15g of protein, so my 33 serve tub has just turned into 66 serves for you.  2 serves a day will mean your tub will last 33 days and at a cost of only $12 per week...that's only 4 espressos.

Half a cup of low fat cottage cheese will give you 20g of protein and 135g of beef, chicken or lamb will give you around 30g of protein.  200g of fish (depends on the type) will give you also 30g of protein.

1 cup of peas will give you 8g of protein and 1 cup of lentils will give you 15g, but again these contain carbs so you need to factor this in to your total calorie intake.

Protein powder salesmen around the world will gasp when I say you don't necessarily have to have protein powder.  Protein is made up of amino acids and these amino acids are in all protein foods, and some non protein foods.  The types and levels vary amongst foods, but not to a huge degree unless you're looking at vegetarian proteins.  Amino acids are used for muscle repair and recovery and most of us don't necessarily need huge amounts of it as our bodies eliminate a large portion.  Even your rice contains amino acids (2g of protein in half a cup of boiled brown rice)  Your half a cup of oats has 6g of protein in it also - so you don't even need to add your full serve of protein to this!

So perhaps you may be able to afford a protein supplement, just simply by looking at your training, protein in your other foods and the amount of protein you need to consume.