Newegg offers the Polk Audio CS1 Series II Center-Channel Speaker in Black for $59.99 with free shipping. That's tied with our mention from two weeks ago as the lowest total price we've seen. (It's a current price low by $31.) It features a 55Hz to 25kHz frequency response, and up to 125-watt power handling.
Note: If you haven't yet, use Newegg’s Android app and pay using Google Wallet to cut it further to $44.99. (This discount can only be used once per account.)