iCoostor via Amazon offers its iCoostor WiFi Smart Plug 4-Pack for $53.99. Coupon code "OPFIOXPB" cuts that to $37.99. With free shipping, that's the lowest price we could find by $6. They're compatible with most smart devices. Deal ends March 28.

Note: The 2-pack also drops to $19.69 via coupon code "TPUZ7YT6" and the 3-pack to $30.39 via "6JCSJ8ES", as listed yesterday.