Aprilaire 700M Whole-House Humidifier with Manual Control. This is what I bought and it does my whole house, plus can integrate into your thermostat if it has the correct connections. It was easy to install as long as you don't mind a little plumbing and low voltage electrical.
Interesting. I was just going by this price for the 700, which is what I paid.
It was $250 with a $112 install charge. I did all of it on Amazon. The humidifier I got is an Aprilaire 700m. https://www.amazon.com/Aprilaire-Whole-House-Humidifier-Manual-Control/dp/B00DJVISBK/ref=cm_cr_arp_d_product_sims?ie=UTF8