Guests who book a stay at W Hotels & Resorts and pay with any American Express card can receive a third free night for stays through Dec. 31, 2012. Visit http://insideflyerus.wpengine.com/link/?7496

Guests who book a weekend three-night stay at participating Starwood Hotels & Resorts in California using any credit card can receive the third night free. Arrive on Thursday through Sunday (all days of the week arrivals are valid at resorts). Use promotion code Z3H for hotels and Z3R for resorts. Visit http://insideflyerus.wpengine.com/link/?7497 for additional details about the California Weekend offer.

Both offers are only valid on stays of three nights booked at best available unrestricted retail rates and advance purchase is required at time of booking. Cancellations and changes are not allowed.

Bottom line: A free third night is essentially the same as getting a 33.3 percent discount on your stay, but be aware that advance payment is required and if you have to cancel your reservation, you won’t receive a refund so only book these deals if your travel plans are rock solid.