Fry's offers a single Polk Audio RTI 12 Floor-Standing Speaker in Black for $299.99 with free shipping. (Price shown in-cart.) That's the lowest total price we could find by $349. This speaker features three 7" woofers, two 5-1/4" midranges, and one 1" silk dome tweeter; it handles 50 to 500 watts of power.
Note: If you're looking for a pair (or more), you'll need to place individual orders or choose in-store pickup.