Bestbuy offers LG - 140W Wireless Rear Channel Speakers (Pair) - Black for $99.99 (orig. $199.99) with free shipping.

Product Description:
Bump up your home theater sound setup with our new rear surround speaker kit that provides improved connectivity and a wireless receiver that’s compatible with select LG soundbars.

• 2.0 Channel 140 Watt Surround Sound Expansion
  Make your home theater sound more immersive with two 2.0 Channel 140W rear surround speakers.
• Wireless Connection
  Easily connect your rear speaker kit to your soundbar without any wires.
• Wider Coverage
  Keep your speakers connected with our newly improved reception distance that offers up to 60% more coverage;² than before.
• Wall Mountable
  Style your home theater the way you want with a wall-mountable design³
• Compatible LG Sound Bar models
  S90QY and S80QY