ST. PETERSBURG, Fla. — Cyber Monday is underway. 

An estimated 75 million people will keep the Thanksgiving weekend shopping rush going today as they continue the search for big deals and deep savings. 

Cyber Monday 2018 is expected to be the largest online shopping day in history, generating a whopping $7.8 billion in sales, a more than 17 percent increase from the previous year, according to Adobe Analytics, which tracks online sales.

A strong U.S. economy, healthy consumer spending and low gas prices could give retailers a lift this holiday stretch. 

Sales during the holidays will be up between 4.3 people and 4.8 people compared to 2017, the National Retail Federation predicts.

Nearly every retailer taking part is offering free shipping, which can cost a bundle. The problem is that discounting is killing the bottom line at many stores.

But beware as security is a major concern. Despite how savy online shoppers may be, cyber criminals are abundant. 

Experts say you should never shop online using publicly available WiFi unless you know its secure. Security officials say to use a credit card for ordering instead of a debit card since the credit charge can be recovered if necessary.

David Thornton, who owns "A Better Choice Network Solutions" in Tampa, said before putting in any of your personal information for a purchase, make sure the site you go to is encrypted. 

Look for "https" in the address bar—if it says "http" the site isn’t secure. He also warns, whenever you do online shopping, always keep a close eye on your credit report.

Below are precautions to take on Cyber Monday:

  • Avoid websites with odd or incorrect spellings of legitimate companies. Domain names that include hyphens are often red flags.
  • Beware of bogus websites promising unbelievable deals. If it sounds too good to be true, it probably is.
  • Be wary of "delivery failure" or "order confirmation" emails for items you did not order. These may be used to gain a consumer’s personal information.
  • Use a credit card for online orders. It is easier to dispute and mediate fraudulent charges with a credit card than a debit card.
  • Use strong passwords for credit cards and bank accounts.

If you believe you are a victim of fraud, contact the department's consumer protection information hotline at 1-800-435-7352. 

Information from CNN was included in this report.