Padida via Amazon offers its Padida Ultrasonic Pest Repeller for $29.99 $25.58. Coupon code "WRE6TITN" cuts it to $19.49 $16.63. With free shipping, that's $11 off and the lowest price we could find. It uses varying frequencies to repel insects in areas measuring up to 400 square feet. Deal ends April 26.