Aptoyu via Amazon offers its Aptoyu 300ml Essential Oil Diffuser for $23.99. Coupon code "QCPBZDTH" cuts it to $11.99. With free shipping for Prime members, that's $2 less than our mention from two weeks ago, $12 off, and the lowest price we could find. It features a cool mist humidifier and seven changing mood lights. Deal ends December 31.