you want a cheap mic preamp, build one yourself. if you just want a battery box there are tons of designs on the web to build one. if you need an actual preamp. i would suggest using a 5532 opamp, good carbon type resistors with mylar or metallized poly caps. many designs can be found on the net. you can have up to about 60db of gain with a 5532. relatively low noise, an alternative would be a TL072.