Mag 10 by bio test is just a post workout whey protein and carbohydrate powder. You can easily make your own version for a fraction of the cost.
When purchasing supplements the brand isn't particularly important. What matters is the ingredient list and supplement facts panel.
For a wheyprotein - you want to see nothing but that in the ingredients list. Wheyprotein, natural flavours, a natural calorie free sweetener like stevia and then maybe some salt, soy lechitin and cocoa powder. There are a lot of good products on the market. I personally use isolation from n2bm.com. A good whey isolate should be pretty much fat and carb free. Isolation has 26g protein, 1g carb, 0g fat per 30g scoop.
For a carbohydrate powder - get a bulk waxy maize or vitargo powder
Use the amount of protein and carb powder you want to get your desired protein/carb ratio