save up, there is nothing in this price range worth dropping the money. Get about 500-600 and you get great opportunities. Look to save for a used UA LA610, or Blue Robbie.

for that price range I like my APHEX 107, its won't pretty up your recording, but it won't make it worse. Although at very high gains it does have a bit of noise. You can get them off ebay for about $100 USD. I have changed the tubes out in mine, to lower gain versions, since I don't typically need that high of gain.

Look for a used API 312 microphone preamp card on eBay. All you need with that card is a + & -15 volts power supply and a couple of connectors. That's a $500 microphone preamp in a different box for only a couple of bills. The soldering iron will cost you four dollars at the local shack. Once you hear that microphone preamp with that lovely input transformer, you'll know everything else is a fake.

Not a fake but an original
Ms. Remy Ann David

First have a look at this http://www.rane.com/note148.html

If you are handy with a soldering gun

http://kleeworld.de/projekte/hamptone.html

http://www.eisenaudio.com/diy500/

seventhcirclestudios.com

http://www.fivefish.net/diy/

http://www.borbelyaudio.com/eb103213.asp

Best of luck....my own personal favorite inexpensive microphone preamp is
the Studio Projects VTB-1 Tube Blend Mic Preamp http://www.studioprojectsusa.com/vtb1.html

I got mine used at GC for $100.00 but they are available on the web for $119.00

Really Nice?

I've been researching the "really nice preamp" from a company called FMR Audio. Check it out:

http://www.fmraudio.com/RNP8380.htm