I agree with the advice given when it comes to radios. A two-channel radio isn't worth buying. Save up for a 4-channel at least. It won't cost much more, and you'll end up buying it in addition to the 2-channel anyway, at which point you'll never look back at the 2-channel.
Keep in mind, the radio is pretty safe assuming you manage to at least recover the glider. The radio seldom suffers any damage, even if the plane is destroyed. And if you do lose the glider, and all the gear on board, you can replace the on-board radio gear for a pretty reasonable price as well.
A 4-channel radio is a good investment. A 2-channel is a costly waste.
Just my 2 cents...