You might find cheaper bulbs from other brands as well......brand name doesn't matter, just the pin arrangement.
Catalinaaquarium.com has 65w 6700K straight pin bulbs for $15: Catalina Aquarium
. That is a great price.
I've used their bulbs before and they are the same as any other when it comes to plant growth and quality.
And 22" should fit in the Coralife fixtures (I have them in my 30" Coralife and 48" Coralife).