I finally approved us for Google benefits for nonprofits, and I am in the process of starting using them, one by one.
The first I've chosen is the ads via AdWords on Google search engine in the coastal part of San Diego County.
This is worth abot $300 a month in advertisement.
After trying various combinations of phrases to fit most meaning into short field, I've chosen this text:
Connect with Secular Humanists | Educational Nonprofit
Join other conscientious atheists for gatherings and talks - we believe in good!
San Diego, CA
This is how it will look on the sites that allow pictures, on Google Search and on Google Maps: