Depending on how competent you feel with wiring/soldering, you can pick up an older 40MHz radio with a bunch of fancy features and then solder a 2.4GHz conversion kit into it. Gets you a versatile transmitter at the fraction of a cost of a 2.4GHz specific model with similar features. The conversion kit I use is by FrSky, and the failsafing and binding procedures on those are fantastic, as a few others will testify. I don't have the links to the necessary components handy at the moment as I'm on my phone but I'll post them up later.