go with the better known brands. eas, prolab, optimum nutrition, designer whey, pro rated, just to name a few. with these you can be sure if its on the label its in the container
you can find 5lb containers for under 30 dollars. these will give you about 70 to 80 servings per container.
you can take it everyday if needed. dont fall for the ones the promise more gains. its just protein in a powder form. nothing more nothing less.
how about whey matrix...? I bought some recently, because they had it on sell for only $15. The container had a dent in it, so they were selling it as a defective product..go figure.