For about $200 you can get a refurb x50 or rx65. I've been seeing the same models on cl as well for <$200 on occasion.
I've had an rx65 (bought when circuit city was closing dirt cheap) for about 5 or 6 years now, its still fantastic especially after tweaking the settings (info is on forums).
Skip whistler, cobra, etc.
link is for escort radar ebay store, they list refurbs there
http://stores.ebay.com/EscortRadar?_...p2047675.l2563