Best Shoe Websites for Quality and Affordable Footwear?

Hello everyone, I'm looking for trustworthy shoe websites that provide both cost and quality. I've tried a couple of local shops, but their inventory is either too expensive or out of current. I'm specifically searching for websites that offer a decent selection of running, formal, and casual shoes. Extra marks for prompt shipping and simple return procedures! Which shoe websites are your favorites that you use and find reliable? Furthermore, when placing an online buy, how can one ensure that the size they receive is correct? Your suggestions and experiences would be much appreciated!