Cafago offers the K6 True Wireless TWS Bluetooth 4.0 Earphones with 2,100mAh Power Bank for $46.55. Coupon code "APV39" cuts it to $33.99. With free shipping, that's the lowest price we could find by $7. These water-reistant earphones feature a frequency response of 20Hz to 20KHz, 32-ohms impedance, and five pairs of ear tips.

Note: they ship from China and may require two to five weeks for delivery. Also, the countdown timer on the product page does not reflect an actual expiration time and resets daily.