My question involves criminal law for the state of: California

I was walking back to my dorm about 50 ft away, ran into an undercover cop. I had beer can in my hand that i had just opened, only 2 sips in, clearly wasnt drunk, and im 18 years old. Ticket is as follows: 25620(a) BP open container Infraction...checked off to the traffic division in oakland. The cops were really chill and joking around with me how i shoulda chugged it when i got it. Said this incident would disappear after i paid the fine. How much do you think the fine is going to be.