Christian Resources International (CRI)
200 Free Street
Fowlerville, MI 48836
CRI is among the largest organizations of its kind in the U.S. Since 1956, it has provided a wide variety of free or inexpensive Bibles and other Christian literature to missionaries who serve overseas, people going on mission trips, and prison chaplains. Nearly all is in English, but they have some in Spanish and other languages. They are glad to recycle most Christian literature as long as it is in good condition. Contact them about sending large quantities. They have sent over 278 million dollars worth of Christian literature overseas (mostly in large sea containers).
CRI also has a program called “Share Your Bookshelf” whereby individuals can send their own extra Christian books overseas.