If you get a good caring person at foot locker, you can get a really good fitting as well. They'll tell you what size you need in both women's and men's and kid's depending on the size of your foot. As will as the width, and how long the arch is. Which really helps in finding shoes. Unless your like me and got tiny feet, and then it's a matter of what they have or can order for you. But at least you'll get the measurements and can shop around, if you don't find anything you like. And even some stores on the web list arch height, so that is really helpful as well.
Kit