Now through 7/2, head over to Staples and snag these Biometric Sport Earbuds with Heart Rate Monitor for only $19.99 (Reg $150!) Plus, if you’re a Staples Rewards Member, you’ll get Free Shipping and up to 5% back in rewards on this purchase. These feature a built-in optical sensor that measures heart rate, which can then be synced with the Runkeeper app. Get yours here.