Well that's kind of an open ended question with lots of answers depending on what it is you want to record and how much work you want to do to get decent sound.
First off, what camera are you going to be using to record stuff with? If it's a 7D then I would say get a small, hand held recorder like the Zoom H1. They commonly sell for $99 and come with a pair of decent, built in mics that will probably do a lot of your recording. But if you were to add an external mic to the H1 then you could do a few more things with the recorder.
If you are using a 5D2 or a 60D then you have a few more options with sound recording straight to the camera. These cameras allow you to override the AGC and actually record some fairly decent audio straight to the camera and then you don't have a lot of post syncing to do. But if you like then you can still do sync sound with a H1 if that's what you want to do.
The small, affordable, short shotgun mics that were made for these cameras usually cost in the range of around $150 or so and are (again) fairly decent. Not the end all, be all of sound gathering, but you said you only have $200 to spend on sound gear. Unfortunately 200 bones doesn't get you a whole lot with sound gear. Personally I like much more expensive mics. I have an affinity for German and Austrian mics that cost in the $1500 and above range, but then again, that's what I do for a living...

It just kind of depends on your camera, how much work you want to do in post and what it is you want to do most. You really can't go wrong with the H1 though.