if it's just vox you are after, the environment is just as important (if not more) as the microphone, so it might be worth investigating that avenue also. I'd suggest spending a little bit more than $150, see if you can get a Shure KSM27 for cheap as possible. If you absolutely MUST stay in that price range, a behringer C1 would do the job, or even an m-audio Nova. One thing you will 100% want to either invest in or make yourself is a pop filter, they go from like $15 to $100, but you can make a cheap dodgy (but effective) one with some stockings and an old wire coathanger