I have compiled a list of Books, Blogs and Websites that I have found and have either tried and tested myself, or have on my list of things to get for my family to help my children learn from the Book of Mormon. Note I say Learn, not just Read.
Most are free, and a few are priced fairly reasonably (all under $20)
LDS Scriptures for Kids
The Author of this Book, Wendy Bennett, had enjoyed sharing a childrens Bible Stories Book with her kids. When they had finished with that they wanted to continue on to the Book of Mormon. The actual scriptures proved too advanced for her children, and try as she might she couldn't find a Childens Book of Mormon! So her and her husband compiled this little book. Their children illustrated it! Not only is this tried and tested by a fellow mormon mommy, she is also the author.
Available on Amazon and Kindle, starting at $3.00
Sharon Anderson is a stay at home Mom that homeschools. She came up with the concept of TimeLines Etc to help teach her kids American History quickly while having fun. She just happens to also be a Latter Day Saint. Which really comes in handy as included in her assorted Packs are The Book of Mormon, Church History, The Old Testament and The New Testament. The packs are $18.00 each, however discounts are offered for multiple orders. There are also some freebie printoffs.
My Fist Book Of Mormon Activity Book
by Laura Kee Rostrom is available through lds bookstore online. It is only $3.95 and has lots of coloring-in-pages and dot to dots along with other simple activities for younger children.