I have the Blue Snowball, only about 60 bucks i believe.
One thing i would recommend you get if you buy this would be a quiet keyboard, specifically those with the cherry switches. The switches are those little things under the keys..the things that make that bit of noise when you press the keys down. If not, you're going to have a ton of keyboard sound in your recording. Of course these are things to worry about only if you are a Gaming YouTuber. I know there is also something called a Shotgun Microphone, these microphones are usually small..about a little bigger than a golf ball, and are really long like a shotgun. They are supposed to pick up sound very strongly coming from the direction right in front of it. I haven't tried the shotgun mic out and don't know for sure if it will also pick up a little bit of background noise. That being said, I have my setting set on my blue snowball to only pick up sound coming in one direction..and it still picks up my keyboard clicks which is off for the side.
These are just some things that i have experience with and thought i should share. Hope it helps you