College Confidential’s “Dean,” Sally Rubenstone, put together 25 of her best tips. So far, the "25 Tips from the Dean" eBook has helped more than 10K students choose a college, get in, and pay for it. Get your free copy: http://goo.gl/9zDJTM
University of New Mexico is about 18-19K for room/board/tuition with an Amigo Scholarship (in-state tuition - your child's current stats qualify). There are also presidential and regents scholarships for full tuition/full ride which are more competitive.
Also second Wyoming and Montana State.
With a reasonable amount of self study and practice tests, my D was able to bring her ACT up by a few points. Hopefully, he can squeak out that extra point with another try. Good luck!