Hello all,
I am a student at UCSD and it is not THAT expensive to live in La Jolla... it just depends on the housing complexes in La Jolla you choose to live in. I am sharing a room and I pay $400 a month, which is not bad at all, and I think that is pretty do-able. 400-500 to share is the norm around here. If you move a little farther out of La Jolla, like Clairemont Mesa, it will be a bit cheaper. Maybe...
Also, Mesa grad housing is not expensive either. I've talked to a few grad students and it's a pretty sweet deal. If you can live there, I would suggest you do.
Good luck in your decisions!