Amazon offers Yamaha YAS-203 Sound Bar with Bluetooth and Wireless Subwoofer for $249.95. ...

NeweggFlash offers its Harman Kardon HKTS 30 5.1-Channel Home Theater Speaker System in Black for $249.99 with free shipping. That's tied with our April mention and the lowest price we could find by $550. It features a frequency response of 45Hz to 20kHz, 8-ohm impedance, four 120-watt two-way satellite speakers, one 120-watt dual-driver center-channel speaker, one 200-watt down-firing subwoofer, and all the necessary cables and wall-mount hardware. Deal ends July 26.

Jet.com offers the Samsung Dolby Atmos 5.1.4-Channel Soundbar System for $780.47 with free shipping. That's the lowest price we could find by $715. This system features Bluetooth streaming, a 15-speaker soundbar (which includes four upward firing Atmos speakers), wireless subwoofer, and wireless rear speakers.
Note: You can score additional discounts during checkout by waiving free returns or by choosing select payment options.

Newegg offers Polk Audio PSW Series PSW10 Black 10-inch Powered Subwoofer Single for $69.99 with code EMCXRHBJ2. ...

As one of its daily deals, Best Buy offers the Bowers & Wilkins Panorama 2 Soundbar System for $999.98 with free shipping. That's $500 off and the lowest price we could find. It features a 50-watt subwoofer, five 25-watt amplifiers, and three HDMI inputs. Deal ends today.

As one of its daily deals, Newegg offers the Yamaha TV Speaker Base for $116.95. Coupon code "EMCSRHBF2" cuts it to $99.95. With free shipping, that's $20 under our May mention, $250 off, and the lowest price we've seen. It fits under most TVs up to 42" and features Bluetooth music streaming, dual built-in subwoofers, and and can learn your TV remote's commands. Deal ends today.

GeekDeal via eBay offers the refurbished Samsung Soundbar with Wireless Subwoofer for $98 with free shipping. That's $2 under last month's refurb mention and the lowest price we've seen. (It's the best deal now for a refurb by $22.) It features a total system power of 300 watts.
Note: A 90-day warranty applies, but it's unclear who backs it.

As one of its daily deals, Newegg offers the Polk Audio 5.1-Channel Home Audio Speaker System in Black for $154.99. Coupon code "EMCSRHBD3" drops it to $129.99. With free shipping, that's tied with our February mention and the lowest price we could find by $20. It features four RM7 Satellite speakers, one RM7C center channel, and one powered 8" subwoofer. Deal ends today.

World Wide Stereo via eBay offers the Denon 7.2-Channel Receiver bundled with a $50 eBay gift card. for $499 with free shipping. Assuming you'll use the gift card, that's the lowest price we could find by $50. It features 3D surround sound compatibility, eight HDMI outputs, seven channels, two subwoofer outputs, USB, color coded 4-way speaker terminals, 95 watts of power, WiFi, Bluetooth, and Audyssey microphone.

World Wide Stereo via eBay offers the Denon 7.2-Channel Receiver bundled with a $50 eBay gift card. for $499 with free shipping. Assuming you'll use the gift card, that's the lowest price we could find by $50. It features 3D surround sound compatibility, eight HDMI outputs, seven channels, two subwoofer outputs, USB, color coded 4-way speaker terminals, 95 watts of power, WiFi, Bluetooth, and Audyssey microphone.