Library Listening Centers

We got a grant for a new listening center, but the debate has been more about how many books we order to go along with the book on CD. For instance, we have an Arthur Goes to Camp CD, so how many copies of books should we purchase to go with the CD? I don't want a zillion of each book -- cause if the CD was checked out and not returned, we have an aweful lot of copies of one title. On the other hand, the smaller the kids, the less likely to share well with others. What do you all think is a 'nice' size? We are a small to mid-sized library, and our budget isn't going to stretch to re-ordering the CD's often.

If you will have school classes coming in you need 30-35 otherwise 10 should be plenty. Just my opinion, take it or leave it.