Oak Leaf via Amazon offers the Oak Leaf 300ml Color-Changing Aromatherapy Essential Oil Diffuser in Wood Grain for $32.99. Coupon code "6ELVJZSL" drops it to $26.99. With free shipping for Prime members, that's the lowest price we could find by $11, although we saw it in another color for $14 less last September. It features a 7-color LED light and auto-shutoff.