Would you like to help the environment and save money at the same time, without much sacrifice? A small step could be to change the font you use when printing.
Three years ago, Ars Technica reported how the University of Wisconsin-Green Bay changed their default front from Arial to Century Gothic to save money. The Century Gothic font uses 30% less toner than Arial to print the same text. In other word, you could cut your toner costs by 30% (or actually, increase your toner supply life time by more than 30%), by simply changing the default font used in your prints.
But it is not quite obvious how much one will save by switching. The University of Wisconsin-Green Bay said it used $100,000 per year on ink and toner cartridges, according to a report from TwinCities.com, and expected to save between $5,000 and $10,000 per year by asking staff and students to use a different font. Not all PDFs and documents are created internally, and those from external sources will most likely still use a different font. Also, the Century Gothic font is slightly wider than Arial, and thus might use more sheets of paper to print the same text, so the total saving depend on the documents printed.
But it is definitely something to consider, if you want to reduce the amount of trash, decrease the amount of toner used in the world, and save some money in the process.
Update 2013-04-10: If you want to know how much ink/toner could be saved when switching between fonts, Inkfarm got a service to calculate the difference between font pairs. They also recommend which fonts to use to save ink. Check it out. :) While updating this blog post, I also came across a blog post from InkCloners, listing the fonts they recommend, with Centory Gothic at the top.