Expositor's Bible Commentaries - about 10 are on sale for US$6.99 each
NIV Application Commentaries - About 19 are on sale for US$4.99 each
Story of God Commentaries - About 8 on sale for US$6.99-$8.99
Zondervan Exegetical Commentaries on the New Testament - About 9 for US$8.99 each
Zondervan Illustrated Bible Background Commentaries - About 9 for US$3.99 each