Charles Ro has the Universal LionChief Remote for $46 plus shipping. (The picture is old, they're selling the current version of the remote.) TrainWorld has it for $45 plus shipping. I'm no Luddite, but I do prefer the remote to using the iPhone app.
Edit to add: 4) You need O-gauge track. 5) Connection from the power source to the track.
Further edit to add: TVS diodes! TVS diodes! TVS diodes! ;-)