One is to get a microphone and a long cable. The other is to get a wireless microphone. The first is a little less expensive - although not much once you buy that long cable. A wireless microphone has a small transmitter built into the microphone housing and a receiver that connects to the camera. Between the two are radio waves, and that means that other radio waves can cause interference.
Conditions can also degrade the audio signals.
Unfortunately, the range of most home wireless remote mikes is rather short. Beyond 50 feet there will almost always be noise creeping in. Get to 100 feet and the noise is going to start to get irritating. Beyond that you might as well forget it. Whichever microphone you get, there are two factors to consider.