Salary of a UI/UX designer at a startup?

I'm about to graduate from college with a Biology degree but I've been doing design work and UI for clients since I was a kid. I am extremely comfortable designing interfaces and experiences and I see quite a lot of job openings in San Francisco (I live about an hour away anyway).

I'm thinking of actually pursuing this as a career, and I always see the same thing: Full-salary + benefits + equity. What exactly is a full-salary for a UI/UX designer at an early-stage companies with funding? I'd like to know so I can plan for the future.