In keeping with President Ezra Taft Benson's emphasis on the Book of Mormon, The Church of Jesus Christ of Latter-day Saints is making its own set of cassette tapes of the book available at a lower cost than commercial outlets.

Book of Mormon tapes have always been available to the blind, said church spokesman Don LeFevre. The decision makes the tapes available to church members at a much more affordable cost.The tapes are being sold for $18 per 18-tape set, between $20 and $35 less than sets offered by commercial outlets. They are available through the church distribution center, and are narrated by Paul F. Royall.

The church also plans to market cassette tapes of the Doctrine and Covenants around Christmas and of the Bible in early 1989.

Lew Kofford, president of Covenant Recordings Inc., said the availability of the cheaper tapes will not affect his company's sales. Covenant produces and sells Book of Mormon tapes, but also markets tapes of music, including the Mormon Youth Symphony Chorus, and dramatizations of scriptural events in radio-drama style with actors.

"We do a very good business," Kofford said. Church distribution is not really competition for his company, he added, because people tend to use retail outlets with which they are familiar and that are convenient to them.

Covenant markets one set of Book of Mormon tapes for $39.95, narrated by former KSL news announcer Rex Campbell, and another set for $54.95, narrated by Charles Freed.

Another company marketing scriptural tapes is Eagle Marketing Corp. of Orem. It offers a Book of Mormon package narrated by Lael Woodburg, a Brigham Young University drama professor, for $49.95.

Steve Shallenberger, president of Eagle Marketing, said the church-produced tapes will not have a serious effect on his business either.

"A small percent of our products are narrated products," he said. People may also show a marked preference for a certain narrator, he added, and buy a more-expensive set of tapes because they like the speaker. Shallenberger said people often consider the tapes of the Book of Mormon "a long-term investment," and will spend more money for what they feel is a better product.