Do you remember when you wouldn't be caught dead in a pair of sneakers outside of the gym? Or how about when you actually referred to your sneakers as gym shoes? We sure do! Those days are long gone, and thanks to recent runway trends, sneakers have become both functional and fashionable. We found 15 pairs of sneakers under $100 (one pair's under $15!) that are so stylish you can even wear them with your favorite spring dresses.