Walmart offers the Honeywell Mistmate Cool Mist Humidifier in Red, Black, or White, model no. HUL520, for $19. (Amazon has it in Black or White for the same price.) Opt for in-store pickup to avoid the $4.97 shipping charge. That's $9 off list and the lowest price we could find, although we saw it for a buck less last summer. It runs for up to 20 hours after filling and features auto shut-off.