If you are planning on using the buddy box system to learn to fly, this pretty much rules out the AM radios.

A buddy box is where you connect a slave transmitter box to a master transmiter. The instructor can then give and take control of the plane via a switch.

When buying used equipment be aware of the condition of the batteries. If they are years old there is the potential they are shot. The only real way to check battery health is with a device called a cycler (does a controlled discharge to measure battery capacity)

My first set (Futaba AM) that I did some horse trading for needed new batts. That set me back $44 for TX and RX packs