Make the most of your library and local book swapping programmes.
Thanks to Nicola for suggesting we check out Good Books. Based in Ponsonby, Auckland, nobody working there gets paid and 100% of the profits go to support projects in collaboration with Oxfam! By partnering with the Paperback Shop in the UK they can supply over 4million titles - and it's growing! And if that isn't enough they also have free worldwide shipping.
Alternatively, Book Mooch is a popular international online book swapping site, although we haven’t tried it and can’t vouch for the packaging.
Buy second hand. I love supporting local second hand bookshops, and am always surprised by all the books available on Trademe.
When you've finished with your books rehome them through the same channels or charity shops and church fairs.
If you buy more then 22 books a year, then you might want to consider getting a digital device so you can buy e-books instead. Under this amount, the carbon emitted from the construction of the reader completely outweighs that of the paper books.