The best humidifier for home use in my opinion and what I have and use is the Honeywell Mist Mate Ultrasonic Humidifier I bought at Walmart for $38.00
It's a great humidifier and works wonderfully and has improved the health of myself and my family.
I've also heard great things about the Dyson 303117-01 AM10 Humidifier but those are a bit more expensive but might be worth the cost if you can afford it.
But if you're looking for a good cheap humidifier then i would recommend the Honeywell Mist Mate Humidifier like I have.