If your kids get good grades, they get a scholarship. So you don't have to pay for tuition. I think you need a 3.75 for a quarter tuition scholarship and a 3.95 for full tuition. Considering the cost at other universities, there isn't any comparison to the price of BYU-I.
Burdening your kids or yourself with either student loans or the outrageous price of another University is not worth it imo.
Here is the link for scholarship info.
http://www.byui.edu/financial-aid/aid-available/scholarships/academic-scholarship