Do you menu

I see a lot of menu makers from other blogs. I go back and forth on this one. My problem is not making the menu itself but shopping based on a menu. I buy my groceries first. I have also in detail figured out the cost of making my menu first and then shopping or shopping my usual grocery list and then making my menu and guess what? It cost the exact same. I even had different things for my menu. So I like to stick with my basic list. How about you, do you grocery shop before or after you make your menu?