As if back-to-school shopping wasn't already a nightmare, experts are warning parents to look out for online shopping scams for school supplies.

With more schools resuming in-person learning this fall, the Better Business Bureau expects a surge in demand and a sharp decline in supply.

The agency is urging shoppers to verify third-party vendors found through ads on social media. "If you see those pop-up ads, use some hesitation and caution with those and double-check the name of the business to make sure they're legitimate," said Sandra Guile, with the Better Business Bureau.

The Better Business Bureau recommends using a credit card when buying online for the additional protections to dispute and resolve charges.