For $200 research the "Little Rat" @:
audioasylum.com (in the Vinyl Asylum)
I use two of these ($25/each as dual monos and they sound very good. They are battery powered and the rechargable batteries (two sets to rotate) and a charger will run just under $50 @ Target.
The minor problem is that they do not seem to be available @ Radio Shack online anymore, however they can still be purchased from other sources (including Ebay).
With battery power they are extremely quiet. I can turn the volume all the way up, (with them in the line/music on mute) and they are as silent as my digital/CD line.
I am (I suspect) the first person to try them as dual mono's and it is well worth the minimal effort. A few people @ Audio Asylum were going to try them in this configuration, but I have yet to hear back from them. By running a single preamp per channel (you use one input and one output per unit instead of the stereo pair of these) the power supply (battery) is asked to do less, which is similar to beefing up the power supply (it also avoids cross talk, as in other dual mono designs, which may in this case increase stereo separation as well).
Theory aside, they sound very nice in my setup (and the investment was approx. $100).
They would however only perform well (based on my experience) with high output cartridges (check my system which uses a Grado Prestige Silver). I have also used them with both SS and tube (active) preamp sections and in both cases the sound was good. As far as a passive preamp section, I "suspect" that the results would not be as favorable unless a "step up" transformer was used (the same goes with low output cartridges) but have not tried this myself.