Besides reducing margins, using smaller font and just plain not printing, we've got a new, free option for saving ink, trees, and also money: GreenPrint is a download (PC only) that helps you to easily print less--no more orphan pages with only a footer because the website page you're trying to print ran over just a bit. GreenPrint also gives you 1-click PDF printing. Oh, and the program keeps track of how much paper and money you've saved as well.
