HarperCollins/Zondervan has put all of their NIV Application Commentaries (NIVAC) on sale for $4.99. If I counted correctly, that makes 32 volumes.
All 27 "books" of the New Testament are represented in these commentaries; however, not all of the 39 books of the Old Testament have NIVAC commentaries for them yet.
The commentary series seeks to bring out the meaning of the Biblical text. However, as the name of the series suggests, it also endeavors to make practical application of the Biblical text, and it does more so than the typical commentary.
You can follow this link to buy one or more of the volumes:
http://media.harpercollinschristian.com/page/32/. If you click on "buy now," you'll see links for three different retailers from which you can choose. A "heads-up":
Amazon sometimes will have a price of
$4.27 on a particular volume instead of $4.99.
How good are these commentaries? Well, like any other set of commentaries which uses multiple authors (that's the overwhelming majority of them), the quality of the content varies from one volume to another. However, I noticed that most, if not all, of the NIVAC volumes have high ratings at Amazon. Also, in the little bit of research that I did, I kept noticing that the authors on different books of the Bible frequently had written commentaries on the same book(s) of the Bible for other publishers and/or series.. What that says to me is that the volumes of the NIVAC are written by
experts on their respective books of the Bible.