'Free' travel can be a real gotcha. Here's when to say yes and when to run away.

Free travel: if those two words aren't enough to make you do just about anything, then nothing will.

The promise of free travel makes travelers run up enormous credit card bills, book airline tickets to nowhere, and ignore reason and logic. In short, the promise of free travel makes us lose our minds.

Fortunately, spring cleaning season is right around the corner, and maybe this should also apply to doing a financial inventory. It's time for a little straight talk about free travel. Actually, there are three flavors of "free" in travel. There's dangerous, there's benign – and there's truly free. The first two are fairly common; the last is not.

Can 'free travel' be dangerous?

Let's start with the dangerous offers. I'm talking about the average "free miles" deal from an airline, easily one of the most absurd come-ons in the travel industry. It's hard to believe that intelligent people fall for this kind of nonsense.

To get your miles, you have to sign up for a mileage-earning credit card and often paying an annual fee for the privilege. That's the first string they attach.

Wait, why are you trying to earn free miles? To get a free airline ticket, of course. And you can't get a free ticket until you've spent enough with that credit card. That's the second string. The more you spend, the more you earn.

Is that really free? No, it's not. You're giving the company something and getting something in return. You paid for it.

To get free airline miles, you have to sign up for a mileage-earning credit card and often paying an annual fee for the privilege.  And if you miss a payment or two on that airline affinity credit card, it will cost you.
To get free airline miles, you have to sign up for a mileage-earning credit card and often paying an annual fee for the privilege. And if you miss a payment or two on that airline affinity credit card, it will cost you.

But wait, there's one more string attached to this deal. Now that you're using an affinity card, you're bound by its customer-unfriendly cardmember agreement. And if you miss a credit card payment or two, you're definitely going to pay the late fees and higher interest rates. So much for those "free" miles.

These types of "free travel" marketing ploys are lies. The people who invented them probably still can't believe no one has stopped them. Only you can put an end to this madness by saying "no" to their gotcha offers.

If you're stuck with one of these worthless pieces of plastic, consider taking a pair of scissors to it. Make no mistake, these cards are nothing but trouble.

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Watch out for these benign 'free travel' offers

A second type of free travel offer involves bending the facts a little. For example.

Kids stay free. Some hotels offer packages to entice families with children to book them. But read the fine print carefully. If you're under 13, you can't just check into one of these properties and expect not to pay a bill. You have to be with a paying adult. That's not free.

Free companion ticket. Again, there's nothing "free" about these offers. To qualify, you have to pay for one ticket. And it can't just be any ticket; it's usually a more expensive one. You might be better off buying two discount tickets and throwing away that companion ticket offer.

Free hotel amenities. Whether it's a "free" welcome beverage or a "free" tour, you typically can't get it unless you're a paying hotel guest. Technically, that means the price of your room covers the cost of that watered-down Mai Tai.

These are little white lies. No, they're not going to turn you into a slave to your affinity card, but they are technically not free. The travel companies that make these offers deserve a slap on the wrist – and you've been warned.

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What's really free in travel?

Fortunately, there's plenty that's genuinely free when you travel. Free Wi-Fi in the hotel lobby or airport, for example. Anyone can walk into a hotel or terminal and log in. You don't have to be a guest, and no purchase of any kind is required.

Free museums are another bright spot. Sara Quiriconi, a yoga instructor and author, likes the airport art exhibits in Miami, Boston and Denver.

"When we're at the airport, the exhibits allow us to learn or experience something new," she says.

Mitch Krayton, a Denver travel agent, says one of his clients discovered a great free feature of Seoul Incheon Airport. The airport offers relax zones with cushy seats where they could nap between flights. They even have free showers. "You can purchase a shower kit for a small fee," he adds. But both the shower and the nap zone are totally free.

Why bother parsing "free travel?" Because words matter. When you offer something for free, and it isn't, you're lying. And if there's one thing travelers are tired of, it's being lied to.

Beware of these 'free' gotchas

Free walking tours. Mitch Glass and his wife took one recently and regretted it. "Near the end of our tour, our guide told us he earns a living from tips, and that while they aren't mandatory, he typically receives between $15 to $25 per person," says Glass, who writes the Project Untethered blog. They ended up spending $50 on a "free" tour.

Free airline tickets. Airlines promise you a free ticket if you earn enough miles. But to earn miles, you have to pay for a ticket and fly. And once you've earned that free ticket, and maybe elite status too, you'll want even more. It's addictive. Don't walk away from this seductive promise – run.

Free breakfast. While it's true that some hotels include breakfast with their room rates, the meal is not free – you have already paid for it. If you don't believe me, try walking into the hotel off the street and asking for your free breakfast. They'll laugh you right off the property.

Free checked bags. No such thing. It's either part of your fare (like Southwest Airlines) or it's not included (almost everyone else). If it's not included, then the airline tries to entice you to sign up for one of its addictive cards, where – you guessed it – your first checked back is free. Only, it really isn't.

This article originally appeared on USA TODAY: Free travel: Here's when to pull out your credit card and when not to