If you're looking for something cheap, it doesn't get much better than free
Athough NewEgg isn't linking to the rebate from their deal page, you can snag a Logitech 600 desktop mic for free - as soon as you get your mail-in rebate processed. Rebate expires November 30th.
Logitech 600 Desktop Microphone (Refurbished) — FREE at NewEgg. Next best is $5 at Meritline.