We find the Atkins individually packaged shakes to be the BEST. We pick them up at Walmart by the case and always have some cold in the fridge. They are so gooooood .
I know the ones you make are a little cheaper; however, this is gona be for life so I think its best to buy the ones that you truely enjoy and look forward to drinking.

Hossdoc

The only truly ZERO carb 100% whey protein powder you will find is the unflavoured and unsweetned (or "Natural"), whichever brand it might be. Flavourings and sweeteners tend to add a very few carbs.

Even if you use the zero carb protein powder, adding flaxseed meal, psyllium husk (fiber carbs), sweetener packets or granular, cocoa powder, cream, etc., all add some carbs.

Only if you find zero carb flavourings, don't add any fiber(s) or cream, and truly zero carb sweeteners (crushed sweetener tablets, liquid sweeteners, pure stevia extract...) will you have a zero carb shake, whatever the recipe.

FYI