I am looking for a cheap powered-microphone set-up. I got a minidisc walkman as a gift, and would like to play around with recording stuff (kids singing "this land is your land", etc). The walkman only has a "line in" input, so I can't use a regular, non-powered mic. I don't need the quality to be that great, I'm just goofing around. So far I have seen the stuff available at soundprofessionals.com. Is there anything more economical?