As a general rule of thumb, anything over an 85 on the ASVAB will qualify you for nearly any position in the armed forces. But there are slight breakdowns within each score. For example, in order to qualify for Surveillance and Communications (SC) in the Army, Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, Auto & Shop and Mechanical Comprehension all require high marks. Though scoring an 85 or above would guarantee you scored in a high enough percentile to qualify for SC.
The Army, Navy, Air Force and Marine Corps each provide tuition assistance (a "kicker") in addition to what you earn through the Montgomery GI Bill. Each service controls the amount of extra money it provides. The Army fund increases the amount of support to as much as $70,000, the Navy fund increases the amount of support to as much as $50,000 and the Marine Corps fund increases the amount of support to as much as $30,000. College Funds are awarded on a competitive basis according to academic merit (i.e., scoring in the top half of the Armed Services Vocational Aptitude Battery). To qualify one must also agree to serve six years.