Never used this one but it is very highly rated, 7 quarts is a pretty decent and versatile size, and right now it's on sale to be in your price range. Its only flaw is that it's not programmable, but I've never bothered with programming the programmable one I have anyway.
I have a Hamilton Beach 7 quart non-programmable slow cooker (http://www.amazon.com/gp/product/B005OYE7HE). The only reason I'm considering this deal is because the Crock-Pot one is programmable (i.e., shifts to Warm automatically). Does anyone know if that functionality is worth it?