The ban was enacted in May and it affects larger retailers like Target and Wal-Mart. The ban will extend to smaller retail stores Jan. 1, 2012.
The goal is to reduce litter and plastic waste by encouraging the use of reusable bags.
Single-use plastic bags cost cities in Los Angeles County up to 17 cents per bag to dispose of.
Shoppers have mixed feelings about the ban.
"I see a lot of people do it. But for me it's a real inconvenience to have to carry a bag and constantly keep one in the car and remember to bring in a reusable bag," said Rick Beechem of Los Angeles.
Others said they don't mind the plastic bag ban because it's good for the enviroment.
"For the environment, I think it's great. And for me, I did have a lot of plastic bags at home and I think it's good to recycle and we need to do something to step it up a little," said Dorothy Quon of Long Beach.
Businesses not offering perishable goods, like clothing stores, are exempt from the bag ban.
Retailers are allowed to provide customers with paper bags. But under the ordinance, they must charge 10 cents per bag.
The Automobile Club of Southern California said it is offering free reusable bags to members and nonmembers for a limited time while supplies last. Anyone interested in getting a bag was asked to call (866) 841-0143 ext. 6573.