Rubberband, headband, hairband, sportsband. What exactly are you asking for? Be a little more specific.

Nike and Adidas do sell sports headband. RM19.90 for one. I have 2, one white one from Adidas and a black from Nike.

Do keep in mind that there's a difference between hairband and headband. Hairband is to keep your hair up and in place during sports, whereas headband is to absorb sweat, preventing them to intrude into your eyes, which can be a painful experience.