Google runs a program for non-profits called Google Grants, and we currently have two NGO clients on it.
It allows to use $329 per day in search campaigns and a max. CPC of $2.
You can’t run campaigns on display, remarketing, YouTube, Gmail or search partners, but even then it is really powerful and of big help to non-profit organizations.
In 2013 they announced that Google Grants advertisers would see their ads below of regular advertisers, but I can’t find documentation regarding how that works nowadays.
They recently announced that you must reach a minimum level of ad quality in order to an ad receive an impression, so QS is something to look closely when using this program.
They recently launched in the UK (https://fundraising.co.uk/2016/11/15/google-grants-for-charities/#.WTct7miGOUk) and they keep adding countries to the list of allowed ones.