I made the 3 month size of course. The lining fabric is from an old sweatshirt Nathan's sister Rachel got rid of, and the outer fabric was from a 25 cent scrap bag my mom bought at a yardsale. There was just barely enough of the fabric to do the outside of the coat, which is why I didn't use it for the lapels as well.
I put 8 buttons down the front. 4 are functional, 4 are decorative. I like the way it looks, because the buttons I had on hand were so small, but I am definitely not planning to do this many buttons on a coat again. (I'm lying. I love buttons!)
I also crocheted a little beanie to go with the coat. Read here to find about more about it.