Here are a couple things to consider before buying that plane and a new transmitter.
First, I am not sure if it is true, but one of the comments on that plane on Hobby King's site said that HK is discontinuing that model. If that is true, replacement parts will probably be limited or unavailable.
Second, check the receivers on your current planes. I suspect they probably use DSM2 or DSMX receivers. If they all use those, you should consider getting one that is compatible when you get a new transmitter. That way, you can control all of your planes with one transmitter. But if you go that route, make sure you get a computerized transmitter with memory for all of your planes. When you have multiple planes, it is a must-have. The cheapest transmitter I know of that meets these criteria is the Orange RX transmitter from HobbyKing. It costs $50-60 USD, which is out of the price range you specified... but orange rx receivers are only about $12. I have never used an OrangeRX transmitter, so I cannot say anything good or bad about it. I have used an OrangeRX receiver and it never gave me problems. The Orange RX transmitter is only DSM2 but I believe the DSMX receivers found in many ultra micros are backwards compatible to work with DSM2 (please correct me if I am wrong).