Thanks to Zondervan Academic for putting these books on sale! The Biblical Theology of the New Testament volumes are all worth owning. I don’t personally think they are the best example of biblical theology since they are purely thematic (e.g., the Luke-Acts volume surveys Messiah, Son of God, Son of David, etc. etc. from Luke 1 to Acts 28). I think we need to move beyond the purely thematic approach; but in any case, the volumes are good references for how themes develop in corpora, which is a good part of biblical theology.
You should also buy Understanding Biblical Theology if you don’t own it, it’s a superb read classifying five different types of BT and a major proponent representing the view.
Lastly, I’m buying Paul and Money as the late Dr. Verbrugge’s final book, and one I’ve seen (in reviews) to be worth reading.