As we prepare to head back to school, a shopping expert is giving advice on how to navigate a possible school supply shortage this year.

Industry experts expect demand to be high for some items as more classrooms fully reopen. With already tight inventory levels and delayed shipments, this could cause a shortage on certain items like backpacks, supplies and footwear. Lindsay Reynolds is a shopping expert at Zulily, a shopping app that has new shops every day offering deals.

"We are hearing and feeling the same constraints that every retailer is feeling right now where we are seeing challenges of product in the marketplace," says Reynolds. "And so, what we say at Zulily is what we say every day. The early bird gets the deal. This year, the early bird gets the deal, the backpack, the crayons and the supplies."

Industry experts expect demand to be high for those items as more classrooms fully reopen. With already tight inventory levels and delayed shipments, this could cause a shortage on certain items.

Reynolds says Zulily is seeing back-to-school shopping trends that get ahead of the shortage concerns by customizing old items.