Using the SDSU net price calculator and the lowest family income I was able to duplicate this estimate. To get this price the OP needs to select living on campus. If instead living at home is selected the price becomes $0.
The OP needs to make a decision. A free college education at a respected school is nothing to sneer at even if it isn’t the entire experience desired. I’m not going to argue against the idea of there being advantages to living away at college, in fact I believe there are. But given the constraints a motivated student could join clubs, take part in campus activities, etc.