I do them for my home childcare. Do your children attend a childcare center or home based program, or even a partial day preschool a few times a week?
I have a small group (6-8 children) and it was free for me to get it all started, and I get free books when parents order online every month (or every other month as seems the norm here). Several of them also have friends, family and co-workers order and I make several age group catalongs available (toddler to early grade school).
I would encourage you to have your child care options set it up! I love the free materials that all of the children in my group can benefit from.