Pathway Reading Series
I have a couple of Amish and Mennonite Booksellers that I purchase from and I find them to be reasonably priced and to provide a good selection of christian books:
Rod & Staff Publishers, Inc., P.O. Box 3, 14193 Hwy. 172, Crockett, KY 41413-0003. This Mennonite company is allowed to have phones, so you can call them at (606)522-4348. Rod & Staff carries a large selection of christian home school teaching resources, story books and coloring books. The shipping costs are low average.
Pathway Publishers, 2580 N - 250 W, LaGrange, IN 46761. These are Old Order Amish, so no phone are allowed. I just love this catalog; it is full of wonderful christian reading materials, fiction and non fiction. They also have farming/gardening books, songbooks, cookbooks, children's books/activities and the popular Pathway Reading Series. Shipping is free for orders over $25 and is $2 for orders under $25! Their prices on books are also very reasonable.