Until recently, the interlibrary loan service offered by my local public library was not on my radar. That is, until I needed to look at an out of print book, Maryland in the World War, 1917-1919: Military and Naval Service Records. The two volume set was published in 1933 by the Maryland War Records Commission. My library did not have this in their collection and a quick search on Amazon.com showed used copies in excess of $130 and a collector's copy for $750. I put in an interlibrary loan request and, surprisingly, I was called to pick up the volume I ordered within about a week. The librarian explained to me that even she was surprised they were able to find a copy, and I was surprised they allowed me take the copy home for several weeks (I even asked if they realized how much the book was worth!).
At the recommendation of Cecile Wendt Jensen in both her book, Sto Lat: A Modern Guide to Polish Genealogy, and her online videos on Family Search (see my previous post), I decided to purchase a copy of Polish Surnames: Origins and Meanings by William F. Hoffman. The second edition of this book was published in 2001 by the Polish Genealogical Society of America (PGSA). There are no copies left for purchase on the PGSA's website and another Amazon.com search revealed that a used copy will run over $100 (three times that for a first edition). The PGSA's website does note, however, that the author is working on another edition to be published this winter. While I will purchase a third edition copy when it becomes available, I want to utilize the resource now. So, I entered another interlibrary loan request and within about an hour I received an email that the request was successful and I will be notified when I can pick it up.
I highly recommend checking your library interlibrary loan service the next time you need a book that is not otherwise available to you. Not all resources may be available this way, but it is at least worth a try. In my experience, it not only saves money, but is also extremely convenient. My library accepts requests on their website, so I don't even have to go in until I have a book to pick up.