I have 2 great sports bras to wear while running, and I am vigilant about rinsing them out immediately after I get them all sweaty, so I can wear them more than once before washing.
Even so, they get really funky, and I’m going to wear them out with washing if I don’t get another couple to rotate them with.
Of course, the kind that I wear/love/recommend (Moving Comfort’s Fiona) run about $50, and mama doesn’t have that kinda money.
Soak in half/half white vinegar and water after you rinse thoroughly for half an hour to an hour. I swear by vinegar for nearly any cleaning task, especially those with an odor component.