Search around the lcd forum. Many people here are selling theirs as well. So check the classifieds too. But I believe that there are several posts around here about cheap ones. Top right...SEARCH button "chep lcd"
Places besides here...ebay of course and Earthlcd.com there are a bunch of others, but search here before you buy. there are all sorts of things you need to look into ie. brightness/nits . you may get a VGA screen that isnt viewable in daylight. So be careful. If you find one, post a link here...there are a bunch of pro's on the board that will help ya out.