Ysmile via Amazon offers two Diaotec Ultrasonic Pest Repellers for $19.99. Coupon code "M8Y6Y2ZU" cuts it to $13.99. Plus, Prime members bag free shipping. That's tied with last month's mention and the lowest price we could find today by $9. This device claims to repel mice, roaches, and other pests via 20kHz to 85kHz changing ultrasonic sounds. It features a night light and coverage up to 1,950 feet. Deal ends March 25.

Note: The 4-pack costs $23.09 with free shipping via the same coupon code.