I'm paying $1400/month for a 17.5'x10' room in a popular part of the city. That's almost $2k/month saved by having roommates.
I feel like I should point out that in most of the country, including large cities, it's hard to even spend $2k/month on any apartment, let alone save that much by opting to have roommates.
... in SF.
In most other cities with many tech employers, NYC excepted, living with roommates instead of in a 1BR isn't going to save you $2k/mo. Median 1BR in Austin or Seattle is less than $2k/mo. Yes, housing is still your biggest cost, but it's so much cheaper than SF, and the taxes are lower than California. The marginal savings you can get by reducing your standard of living aren't as huge as in SF.