Logos Bible Software has some great commentary deals including:

•  Doug Moo on Romans
•  G.K. Beale on Revelation
•  Derek Kidner on Psalms
•  Wenham on Genesis
•  D.A. Carson on John
•  Dale Ralph Davis titles

Notable Kindle Deals:

• The Gagging of God: Christianity Confronts Pluralism by D.A. Carson
• Michael Horton’s two volumes on Justification: Volume 1, Volume 2
• Pilgrim Theology by Michael Horton
• Jared C. Wilson’s The Gospel-Driven Church: Uniting Church Growth Dreams with the Metrics of Grace
• Carl Trueman’s Grace Alone—Salvation as a Gift of God: What the Reformers Taughts…and Why It Still Matters
• Thomas Schreiner’s Faith Alone—The Doctrine of Justification: What the Reformers Taught…and Why It Still Matters
• Stephen Wellum’s Christ Alone—The Uniqueness of Jesus as Savior: What the Reformers Taught…and Why It Still Matters
• Matthew Barrett’s God’s Word Alone—The Authority of Scripture: What the Reformers Taught…and Why It Still Matters
• David VanDrunen’s God’s Glory Alone—The Majestic Heart of Christian Faith and Life: What the Reformers Taught…and Why It Still Matters
• Wayne Grudem’s Bible Doctrine: Essential Teachings of the Christian Faith 

Update:

• Out of Silent Planet by C.S. Lewis
• Prepared by Grace, for Grace: The Puritans on God’s Way of Leading Sinners by Joel Beeke
• The Gathering Storm: Secularism, Culture, and the Church by Albert Mohler