Oak Leaf via Amazon offers the Oak Leaf 140ml Color-Changing Aromatherapy Essential Oil Diffuser in Bamboo for $25.49. Coupon code "XVOIXOPB" drops it to $17.99. With free shipping, that's a $2 drop from three weeks ago, $52 off list, and the lowest price we could find. It features a 7-color LED light and auto-shutoff.