Bestbuy offers Insignia - 114" Outdoor Projector Screen - White for $79.99 (orig. $249.99) with free shipping.

Product Description:
Captivate your audience with this Insignia 114-inch inflatable outdoor projection screen. The audience viewing area is maximized at an easily-viewed height of 83 inches and width of 115 inches. An included air pump lets you quickly and conveniently set up your screen, and the tie-downs keep it secure in various weather situations. This Insignia 114-inch screen provides a versatile, easy-to-use solution for outdoor presentations. 

• Compatible with most home and business projectors
  For versatile use.
• 114" diagonal screen
  Everyone in the room can easily see the movie or presentation.
• Inflatable Projector Screen
  Inflatable screen fully inflates in seconds with the included air pump, and the carrying case lets you easily transport it wherever you go.