I've always liked Futaba, here's one option. Buy the 4YF from Tower hobbies for $129.99. They'll give you $10 off any order between $100 and $149, so the price of the system will be $119.99. They also have a $20 rebate, so the net price will be $99. Later, if you decide to buy a 6 or 7 channel computer radio, your entire flight pack (receiver, servos, battery, etc) will work with the new system.

If there is room in your budget to spend a little more, you could buy the 6EXA. Current cost is $179.99 less $15 for orders between $150 and $199 gives you a net cost of $164.99. The advantages of a computer system include end point adjustment, electronic trims, dual and exponential rates, and throttle cutoff. I chose this radio when I was getting back into the hobby and am glad I did. I actually ended up buying a 4YF also so I had a backup transmitter and a second flight pack.