One Costco member learned the hard way that a typo in a web address can really cost you!

Allen Stern told NBC Bay Area that when he went to navigate to Costco's web site, he mistakenly added an extra "o" — so it was C-o-s-t-o-c-o.

The site looked legit, complete with Costco’s logo, so Allen didn’t think twice about a survey he was asked to complete.

RELATED: 9 things to know before your first trip to Costco

Typosquatting: What you need to know 

To make a long story short, Allen filled out the survey that offered a free bottle of face cream if he paid shipping, but he later received several charges on his credit card bill.

When he complained to the real Costco, he learned that he was ripped off by the fake website.

NBC Nightly News picked up the story and reports that this is called "typosquatting." Criminals will buy website domain names that are very similar to popular sites with the intention of taking your money!

There have been bogus sites that are just a letter or two different from Netflix, Southwest, Verizon, Google and more.

The deceptive website that Allen visited has been shut down, but who knows when the next one will pop up.

The best advice from internet security experts is to double-check your spelling! Take a moment to proofread so that you can avoid the headache Allen had to go through!

RELATED: Costco’s CEO shares 13 secrets with Clark to help you save money

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