My favourite hotel on my favourite beach anywhere was the finish of an episode of Amazing Race. Cool.
Only 1200 meters from the breathtaking and legendary Mayan ruins of Tulum, an exclusive and quiet oasis can be found: Diamante K. It lies on beach front property of over one acre, and is surrounded by more than 200 palm trees.
Diamante K is an ecological hotel which features 30 cabanas; all powered by solar energy and located only 20 meters from the sea and a beautiful private beach.
Rick McCharles 
Their web site is very coy about the price.