Are you trying ways to Strength your foot/ankle? Here is a $25 solution. During my trails runs, I had a lot of ankle rolls. I was suggested by many trail runners to get a Balance Board. I have been using this board since Feb 2013. I like it, and I think it is helping me. At the beginning, it is bit harder, but once you get used it works very well. I stand on it all day at work. I heard it has benefits beyond ankle strength.
I have one of following board from The Academy. http://www.academy.com/shop/pdp/bcg-8482-wobble-board/pid-166855?color=Black%2fBeige&N=668341341&Ntt=Wobble+Board+Balance&Ntk=All