Renting apartment in SF?

I am thinking of renting apartment in SF and I am college student. What is the average price for an apartment in SF? Is lower nob hill around union square safe place and nice place? I saw one apartment which is a studio and it cost about 1800, Is it average price or is it expensive? It is high rise building though. PLease help me if you have other suggestion. I want to live in safe and luxury neighborhood with decent price.