Invest in some moisture-wicking tops as well. A cotton tank top is your worst enemy, trust me. Look for ones that have a high cut under the armpits so that you don’t chafe there either. It should be fitted enough that you don’t have fabric flapping everywhere, but not too tight that you’re self-conscious or feel constricted. And if you’re serious about running, buy a bunch. You won’t have any excuses not to run if you always have clean clothes to wear.