David is exactly right.

The flight pack that you get with a basic four channel is identical to the flight pack you get with a computer six, and guess what? When you buy a four channel you are really buying servos, a receiver, a switch harness, a battery charger and a set of airborne and transmitter batteries. They throw in the four channel transmitter for free.

THis means that when you do actually need a computer radio, you will already have a spare flight pack and an extra charger and transmitter battery, for less money than if you bought the 6 channel first and then tried to piece together a flight pack to equip a second plane.

Also, for the last five years I have been saying that next years computer radios will be cheaper and have more features and I have not been wrong yet. Don't buy a computer radio until you need one, and you don't need one to learn how to fly.