Chateau de Beaucastel is under 50 and probably the best option. Its also fairly easy to find.
I dont have much exposure to Bordeaux, but there isnt much under $50 that wouldnt be better replaced by something else from say California. Robert Foley Claret would be an excellent choice but that is about $100+ a bottle.
Burgundy anything with the words Clos Saint-Denis or Gevrey-Chambertin on the bottle would probably be a good match and in your price range.