Aptoyu via Amazon offers its Aptoyu LED Essential Oil Aroma Diffuser / Cool Mist Humidifier 2-Pack for $20.99. Coupon code "CKWR78SG" cuts that to $12.99. Plus, Prime members receive free shipping. That's $8 off and the lowest price we could find. It features seven LED colors with adjustable brightness and a 120ml tank. Deal ends April 30.