Well, it really depends on how much in student loans you want to take out. How much will Mommy and Daddy be able to help you? As for me, I'm married so I will have to take out the maximum to supply my wife and kids while I make my way through school. So, if you go look at tuition on the LLUSD website (w/o taking inflation into account), and assuming you're taking the full amount in loans out...you're probably going to be taking out around 77k per year...this is what I hear from the LLUSD c/o 2014 (class that entered this year). So, you multiply that x 4 and you have yourself a hefty ~310k in loans. The tuition here is around 55k per year...so they were telling me (last year's entering class) that you get back about $1,500 per month to live on.
USC is going to be a lot more for reasons that someone else has stated above me. The living expenses in LA will literally eat you alive. I would say that if you end up going to USC...the only big difference will be that you will not see as much of the money (1,500) every month as you would a LLU, for obvious reasons such as rent, living expenses, etc...I'm sure USC gives you an excellent education, and honestly if you're going to commit yourself to the steep loan amount at LLU...you should probably just chose the one you want. Look into the PBL and see if it's something you'd enjoy, because the last thing you want is to be absolutely miserable for what may well be the roughest four years of your life. Best of luck to you!