Walmart offers the PureGuardian 10-Hour Ultrasonic Humidifier in Pink or Blue, model no. H900, for $19.99. (Amazon charges the same with free shipping for Prime members.) Opt for in-store pickup to avoid the $4.97 shipping charge. That's the lowest price we could find by $4, although we saw it for $2 less last month. It features quiet operation and low and high cool mist settings.