Home Depot offers 1 gal. Digital Evaporative Humidifier, for $62.99.
Free Shipping

Digital humidistat (35% to 85%) or continuous operation
Filter captures minerals and deposit - no white dust
LCD panel with filter dirtiness indicator
1 gal. (3.7 l) water tank
2 fan speeds
1 to 10 hours timer
Easy to use controls with LCD panel
ETL
Designed for rooms up to 450 sq. ft.
Evaporative humidification with air circulation draws dry air in and pushes moist cool air back into the room