CSHope via Amazon offers the CSHope Ultrasonic Pest Repeller 4-Pack for $35.99. Coupon code "CSA7BLKY" drops them to $29.87. With free shipping, that's tied with last week's mention as $6 off and the lowest price we could find. These plug into a wall outlet and emit a frequency of 22-65KHz, which is claimed to deter insects, spiders, mice, and more. Deal ends July 30.