The main difference between collision and comprehensive coverage comes down to the question of what the driver controls. Collision insurance will cover events within a motorist's control or when another vehicle collides with your car. Comprehensive coverage generally falls under "acts of God or nature," or things that are typically out of your control when driving. These can include events such as a spooked deer, a heavy hailstorm, or a carjacking.
USAA is likely the best company for you if you are in the military or were in the military. USAA is highly regarded by the J.D. Power survey, only placing second to the Texas Farm Bureau. USAA also offers great discounts for cars parked on military bases. USAA also offers cheap rates--in many cases cheaper than GEICO. We found you may be able to get liability insurance for around $450 per year, and around $900 per year for full coverage in Dallas through USAA.