Sometimes you have to wonder if marketing folks use a different dictionary.

Wyndham Hotels has a 4th Night Free deal on the table at nearly 50 properties in the US, Caribbean and Mexico, from hustle-and-bustle big city getaways to sun-soaked tropical spots.  We decided to check out this offer at the Wyndham Sugar Bay Resort & Spa in St. Thomas, US Virgin Islands.  This popular resort welcomes families with a kids' club, three freshwater pools, private beach, loads of water activities, and—a natural kid pleaser—daily iguana feedings.

We test-booked this offer for a February four-night stay for a family of two adults and two kids, and found a nightly rate of $485 for a limited-view double room. Once the fourth night is deducted at check-out, your lodging tab would come to $1,455 before the 8% occupancy tax and 10% resort fee. 

Don't get us wrong: Getting a free night and saving $485 on a four-night stay would be undeniably awesome. But there's one little hitch: You can book the exact same four-night stay for the exact same dates in February in the exact same room category for a lot less without this offer. The resort's best-available rate is $205 a night, or a staggering $280 less than the promo rate. Book the best-available rate, and your four-night stay will run $820 before taxes and fees—a whopping $635 less than you'd pay with the fourth-night-free offer.

In this case, freedom's just another word for jacking up the rate. Your defense, as always: Do the math.

By all means, if you and your calculator find a Wyndham property where the fourth night is indeed free, please let us know.