For when the library just won't do...
We gave our boyfriend a used book for Christmas. We couldn't rationalize the waste of paper for a brand new version, but we also couldn't help but feeling, well, a little cheap?
We debated the decision, ultimately deciding he'd agree more with the green purchase. (Which luckily, he did.) There's so many outlets now besides your local book store, even Amazon and Barnes and Noble let you purchase used copies.
They're not only cheaper, but you can often see the seller's location, so you can choose someone close to home to reduce shipping distance and costs.
While we might think twice about giving a second hand novel to someone we don't know that well, (and knowing that the author won't benefit from the sale) for us, used is still the way to go.