For post workout shake I buy some of that gatorad mix and mix it up with water, 1/4 of a bananna, and my strawberry protein. It is the best I've tried and it is not very expensive. But don't drink this as a meal replacement the carbs are way to high glycemic.
For my regualr shakes I use water, flax seed oil, glutamine, protein. Hold your nose on this one because it takes terrible.