You know what they say: “If it’s too good to be true, it probably isn’t.”

Yet, dozens of people fall for scams that promise them the moon — and they often times do not deliver.

Because of this truism, the Federal Trade Commission (FTC) is warning of an uptick in free trial scams. The scams come in several shapes and sizes, but most look something like this:

You see an ad from Netflix or a cosmetic company saying "Congratulations! Here's a free temporary subscription!"

It's free, right? The only catch? There is none.

That is until you’re asked to pay for hidden fees, and shipping and handling when it’s too late to back out. Or, the screen prompts you to share all your financial information even though you didn't click "add to cart".

In other words, there’s hardly a “free trial” that won’t cost you big.

In one scam, a company aggressively advertised “free trials” for skin care products, dietary supplements and e-cigarettes on popular websites. The lucky customer only needs to cover the cost of shipping and handling.

Of course, the product isn’t free and the victims sometimes pay close to $100 in fees before the first shipment. Worse yet, they get this same fee each month for the next year. With no way to back out of their contract until the 12 months are up.

In another scam, customers share payment information for the $1.03 to cover shipping and handling for the “free” products. After the order's placed, another screen with a “Complete Checkout” button appears. Shoppers that click the button agree to pay for monthly shipments of the product for a cheap $94.31 each month.

Then, another "Complete Checkout" button appears!

Again, some customers click this button. They're forced to pay a $94.31 charge each month. Consumers who take the bait twice ended up with a total monthly charge of $188.62 – plus shipping!

Another free trial scam lures shoppers into signing up for a 12-month trial subscription to a popular service, like Netflix, for free. The company advertising for the free trial isn’t Netflix at all; it was a group of scammers. Once redirected to a new web-page, victims share their sensitive information to qualify for the trial.

You can guess the ending. The scammer made off with the consumer’s information.

Don’t let this happen to you! Here’s how to steer clear of free trial scams:

Do your research.

A quick online search of the company name with words like “scam” or “negative review” should give you a basic idea of what the business is all about.

Read the fine print.

Too often, there’s no way to refute charges relating to this scam because the consumer agreed to pay them. Don’t click anything without reading all the terms and conditions attached to the offer. If you can’t find any, or you can’t understand them, opt out of the offer immediately.

Look for an exit strategy.

Is there a way to cancel the offer? Can you change your mind about the product? If you only have a small pocket of time to cancel the trial, you might be looking at a scam.

Check your information.

Always review your credit card and checking account statements. This way, you’ll immediately spot anything suspicious and you’ll be able to determine if you can back out of a shady deal.

Never share sensitive information online.

Unless you’re absolutely sure you know who you’re dealing with, it’s difficult to know if a website is 100% secure.

Check URLs.

When signing up for a free trial, you’ll usually be redirected to a new site. Check the URL of the webpage and determine if it matches the company you are allegedly dealing with.