What are the best websites to buy sneakers?

I'm going to be travelling to LA soon and theres a whole lot of heat I can't wait to cop. However, I'm worried that all the shoes can't fit into my luggage on the way home. So I figured I would go to a store, try on a pair of shoes for sizing, then try to look for it online. The thing is, since I'm fairly new to the game, I'm not familiar with which websites to go to. I'm looking for both retail stores and resellers but leaning towards more of the retail side like footlocker cos I'm not looking for super rare jordans, just want a few pairs of casual kicks like AF1s, air max, zx flux, etc (these are super expensive here in Singapore which is why I'm waiting to go to LA to cop). Thanks for the help!