Thumb Score: +26 Yosmart via Amazon [amazon.com] has for Prime Members: YoLink Water Leak Smart Starter Kit w/ Hub + 4-Pack Sensors for $39.99 when you 'clip' the 20% coupon on checkout page. Shipping is free. Product Description from Amazon[LIST][*]"SMART WATER STARTER KIT" YoLink Hub Leak Detection Starter Kit, including one hub and quantity four Water Leak Sensor 1.