I am wondering if it is legal to work more than 40 hours a week without overtime pay. Also, I want to make sure how much one is supposed to get breaks when working 8 hours a day.

Generally speaking, it is not legal unless you are an exempt employee. Your classification is dependent upon what kind of work you do. Here are the requirements for meals, breaks, and overtime pay in California.
http://www.dir.ca.gov/dlse/FAQ_MealPeriods.htm
http://www.dir.ca.gov/dlse/FAQ_RestPeriods.htm
http://www.dir.ca.gov/dlse/FAQ_Overtime.htm