Walmart offers the Sunbeam Ultrasonic Humidifier, model no. SUL495-UM, for $30. Opt for in-store pickup to avoid the $4.97 shipping charge. That's $13 under our mention from last September and the lowest price we've seen. (It's a current low by $16.) This humidifier uses ultrasonic technology, runs up to 24 hours per tank filling, and features automatic shut-off.