A cheat sheet from Gott Advertising:
Google Grants is a product offering that looks and smells just like Google AdWords, yet it has special rules, which change on a fairly regular basis.
1. Most Grants are based on a $333 a day spending limit, with no rollover dollars. We prefer that you use it rather than lose it.
2. The bidding limit per keyword has been raised to $2. Surprisingly, it's not always in your best interest to bid the most you can.
3. Paid accounts on AdWords have priority over Grants accounts. We find strategies to work around those competitive limits.