If you're single, just cut your expenses and stay in the Bay Area. Get rid of your car, get roommates, stop eating out. It's much easier to cut your spending than move, and you will definitely be giving up opportunity and intellectual community no matter where in the world you move compared to SF.

Also, Berlin fits your criteria.

If you just want somewhere cheap try Thailand. Many coworking spaces, but harder to find a startup community. The language barrier won't be a problem because of tourism and the polite culture.