|This isn't a sewing tip, but one related to most sewer's journey through their hobby. I posted a book review on Pattern Review recently and realized I had taken for granted that everyone knew you could purchase used books on line.
Some sewiing books are a gamble in terms of laying out hard earned dollars, and libraries don't always have the book you are looking for. In this case, you have a third option. By it used. Both Amazon and Barnes & Noble tap into used books sellers, and there is also my favorite: www.alibris.com. As someone else pointed out, there are other sites like www.abebooks.com.
The prices will be all over the map. Don't judge based on price, judge based on condition. I've had at least 100 experiences buying via alibris and have never had a bad one. And I've saved tons of $$$, and my judgement mistakes weren't nearly as painful.
Lastly, just a warning: For used books, I prefer *not* shopping off Amazon.com. If you go to alibris.com or abebooks.com, you can actually read details about the condition of books. If you shop on Amazon for used books, you can't easily get to that detail.