I usually purchase most things online - it's just easier for me personally. There's not the hassle of pushing past other people as well lol
The stores I usually look at online is HotTopic, Forever21, and Heavy Red. THEN, there is *always* Ebay and Etsy. com Etsy is more for a "unique and one-of-a-kind" look and Ebay is good for, obviously, just trying to find something cute and fashionable... and cheap! I haven't had any trouble buying shoes or clothes from offline really. Usually they have a description of the measurements of the sizes and everything.