I have found that eBay and amazon.com have the best deals on screens as far as I know.
I bought a 69" x 92" 2.5gain Glass Beaded Da-lite Model B manual pull down screen for just $124.80 plus $37.17 shipping, through projector screen central on eBay.
http://search.stores.ebay.com/Projec...648921QQsofpZ0
http://cgi.ebay.com/MODEL-B-Pull-69x...QQcmdZViewItem