Google Grants has always stated that they will give $10k of free advertising to qualifying organizations, and a further 30k of advertising at a 5% charge, for a total possible of $40k worth of adwords for $1.5k. Up until recently they haven't enforced this rule, and qualifying advertisers have been spending well north of the $40k limit. Last week Google started sending out letters to inform advertisers that they were enforcing the spending cap as originally detailed...

http://rbdrodeo.com/2007/09/13/google-grants-enforces-spending-cap-policy/