Erligpowht Direct via Amazon offers this 500ml Wood Grain Essential Oil Diffuser for $21.99. Coupon code "RFHZEJAQ" cuts it to $12.99. (The on-page coupon doesn't stack.) Plus, Prime members bag free shipping. That's $2 under our mention from two weeks ago, $37 off list, and the lowest price we could find. It features up to 18 hours of continuous use, a timer, auto shutoff, and seven changing mood lights. Deal ends May 31.