you should get a USB mic then. otherwise you're going to bring your budget up quite a bit between the mic and an interface / preamp.
check out these (searched usb microphone on amazon):
https://www.amazon.com/Blue-Microphones-Yeti-USB-Microphone/dp/B002VA464S/ref=sr_1_7?ie=UTF8&qid=1474038764&sr=8-7&keywords=usb+microphone
i'd recommend one of the Blue's, or the last one, the ATr2500.
We use this at GutPunch Gaming: http://www.amazon.com/Blue-Microphones-Snowball-Condenser-Microphone/dp/B006DIA77E/ref=sr_1_1?s=electronics&ie=UTF8&qid=1436295696&sr=1-1&keywords=snowball and it's fantastic. If you're willing to go up to $30 I'd recommend pushing the boat out for the Snowball at $49.99. It's $20 more but it's more of an investment as the Snowball is very well built and will last you a long time. The quality for price is just unbeatable in my eyes (or should I say ear? No?)
I guess it depends on what kind of setup you want though. Those mics appear to be a bit on the cheap side, in terms of sound quality. Just from looking at the reviews I can see a few people mentioning buzzing or general noise from the mic.
What kind of mic? I've been nearly paralyzed with indecision.
There's the blue snowball and blue snowball ice, which are commonly used, but I'm concerned about the direction-sensitive reception. I don't want the microphone to have to stand in front of the monitor and block my view just to pick up my voice. The former option has an omnidirectional mode, which may solve this issue, but I don't know.
Then there's the MXL AC404 conference mic, which a friend of mine has. That's omnidirectional only, but apparently works pretty well, but it is also the most expensive of the three.
Ideas?