I would LOVE to work out of my local library, unfortunately, here in Austin libraries have the policy that meeting rooms etc. are only for non-profit groups that are open to the public. No private meetings, no "open to the public meetings" that are run by for-profit companies. I suppose your garage startup could probably _get away with_ meeting there, but it's a big no-no.
The private meeting rooms were nice, but most of the time we just worked from the study desks. Even when we had the private rooms, there was always a feeling of time pressure in them. You might need private space a lot less than you think you do.
Yea, the private rooms at my local library are made almost obsolete by the open study tables and desks there. For one, you don't have to worry about the constant time restrictions, and the extra ventilation doesn't hurt either.