PHOENIX - It doesn't matter if your kids are already back in class or are about to be, a RetailMeNot survey finds nine out of 10 parents are still stressed out.

"They're stressed out about how many things they have to buy, that back to school list is getting longer and longer,” said RetailMeNot’s Sara Skirboll. “What that means for parents is that you don't necessarily have to do all your back to school shopping in one weekend."

Another back-to-school survey by Deloitte found three out of four parents will at least start their shopping online. This can also reduce stress, according to Skirboll.

“They're doing a lot of searching for what they need in terms of apparel and even technology on the internet this year," Skirboll said.

Waiting until after school has started to finish shopping is another good idea, so you can get everything on the teacher's list in one trip.

And if your child needs musical or sports equipment, think about renting instead of buying.

"I recommend don't necessarily go all-in and buy a lacrosse stick or buy a piano or something like that,” Skirboll said. “Look into renting."

Back-to-school season is one of the busiest times for retail -- second only to Christmas – and doesn't end until September.