Travel Up via TripAdvisor offers stays at the Westin Resort and Spa Cancun in Cancun, Mexico, with prices starting from $107.10 per night as provided by ShermansTravel. (We found this price for a 4-night stay on August 22.) That's the lowest nightly rate we could find by $13. This 4-star resort has an Expedia rating of 82% based on 2,793 reviews. Book this travel deal by July 31 for stays through August.