I usually run by Ross, Marshals and the Thrift stores when looking for my commuting gear. I found that the name brand athletic clothes (Under Armor, Reebok, Nike, Asics, Adidas, etc.) are much better than the cheaper Walmart brands (Hanes, Starter, etc.). They are cooler, made better, and will last much longer.

Buying the name brands from the discount/thrift stores makes them worth it. Full retail price is ridiculous.

For long sleeve summer shirts, maybe look at the soccer shirts.