This is an excellent tool for any Sunday School teacher due to the insurmountable amount of information it supplies especially when it comes to the background leading up to the weekly lesson. I was the only teacher using it three years ago and now all the teachers in my church use it.
Christianbook.com is the most reasonable site that I've seen since I've been shopping online for church resources. Before ordering from Christianbook.com, I ordered from another site and dreaded that I never clicked on this site, but when you learn better, you do better. This will be my site for ordering church resources and a few more items. This is the site for me.