Perhaps you've seen it on social media; a post that claims to be giving away gift cards from popular gas stations. One such post which made the rounds on Facebook in June uses the Shell gasoline logo and offers a $500 gas cards to help battle rising gasoline prices. It directs viewers to click the link to receive the gas card. But Shell did not authorize the post and it is one of many scams which may be popping up around the nation. "We can confirm these ads are falsely purporting to be Shell by imitating the brand," said Natalie Gunnell, spokesperson for Shell. "We are not providing those services claimed in these Facebook ads. Patrons can save at the pump via our Fuel Rewards Program." Gunnell added that the company has notified Facebook of the fraudulent ads.

The Better Business Bureau (BBB) warns that such online offers are a common tactic of scammers to obtain user's credit card and personal information. The Shell Facebook ad told viewers that in order to receive the gas card they would have to pay a small fee. One consumer told BBB Scam Tracker, "They said I won a Shell gas card and had to pay $1.95 for shipping. A day later they took $89.95 out of my account. I called about the charge and they fixed it but the next day another $89.95 was taken out again."

In addition to credit card information scammers may also request personal information such as phone number, home address, and birthdate. Sharing these details with strangers can open the door to identity theft.

The BBB offers these tips to avoid being scammed:

Never pay to win. No legitimate company or organization will ask you to pay money to receive something you've won. If someone asks you pay even a small fee to receive a prize, you are likely dealing with a scammer.

Do your research. Imposter scams are all too common. If a large or well-known company appears to be offering you a free gift or prize, do some research first. Go to the company's website by searching for it online via a search engine-NEVER follow the link they send you. If the company is indeed participating in some kind of giveaway, you will find information on it there or a phone number to call and confirm that they are.

Don't act on impulse. Scammers are depending on getting you so excited about receiving something for free that you won't stop to think about the suspicious details of them contacting you. Use good judgement and question any offer that seems too good to be true.

Never give personal information to anyone you do not know, including credit card numbers.

To find out more about scams and how to avoid being scammed, or to report a scam, contact the Better Business Bureau at http://www.bbb.org.