Youre gonna need the actual radio, make sure it comes with the mic. You'll also need an antenna, I use a magnet mounted one because theyre super easy. It should come with the wiring and the jack to hook it up to the radio. Thats pretty much all you need.
I have a cheap radioshack radio with a magnet mounted antenna that had 17 feet of wire.
Not man people go on the radios actually. I just use it to bullshit around with my friends that have one. Theyre fun if youre going camping or out in the desert with your friends in a bunch of cars and you can talk shit and stuff