Not sure about the colors, but you should be able to pick-up an airbrush for about $20 and a can of propellent for another $8. I believe there are some starter kits that include the propellent.

For modern US desert sand use MM #33531. Supposed to be a perfect match for current sand CARC paint. I was at Ft Hood in 1990 when Iraq invaded Kuwait. Our Battalion was in the middle of getting our tanks painted Woodland Camo .. when they stopped and started to re-paint them desert sand. The very first vehicles they painted was a M1 (not M1A1 .. we (1st Cav) didn't get those until we were in Saudi Arabia)) .. a M113 and a M88. My understanding was that the CARC (Chemical Agent Resistant Coating) was a two part paint. Well .. they got that first mix .. mixed up big time! We came to the Motor Pool the next morning .. and stopped in shock. There .. at the end of the Motor Pool .. were these PINK vehicles. I don't mean .. that the sand color was pink tinged .. I mean they were as PINK as a baby's bottom. From that I expect that if you are a bit off in the color it won't matter .. well .. as long as it's not pink.