Hi Kandeya,
Usually people start looking for housing a month or two prior to the fall semester. I did spend the $20 for cal rentals and depending on your needs and budget, it can be useful. I found a place through there and would recommend at least checking it out once. C'mon, $20 won't kill you (though it can take away a week's worth of grocery) haha.
P.S. Make sure you're an informed renter. Ask ALL the basics such as: rent, deposit, lease term, parking, utilities (included or not), size of room, internet, etc. Generally speaking, I am more in favor of the people who show lots of pics of the rental place (means more or less they've got nothing to hide).