How Much Time Can You Get for Stealing

My question involves criminal law for the state of New Jersey.

What would be the maximum fine for someone who shoplifted at pathmark? No police were called. The guard just pulled her into the security office and questioned her. He wrote down her address, phone number and the amount of money she had with her. She had to sign an agreement saying she is never allowed to return to Pathmark or the stores affiliated with it. The guard also said Pathmark might or might not fine her. So my question is what is the maximum amount they would fine her? and would this go to the police?
Girl is 18 years old. The things she took amounted to about $20.

New Jersey is tough on shoplifters. The fine will be atleast $150.