Lipo- TX/RX

[MetalMan]

You could use very inexpensive cells for the TX, like 2C cells. For the RX, anything that can handle about 4amps continuous is fine.

IMO, don't use a Lipo pack for the RX, unless you can find something that will cut off at 6V (which could be disastrous, as the receiver would lose its signal). The TX Lipo pack should be fine, as long as you do keep the cells above 3V.