If you look on the Faithlife blog you will see an offer, which closes tomorrow, for seven discounted books. I would recommend that you consider getting one or both of the books by Tozer 'Renewed Day by Day' which are a series of helpful devotional readings for each day of the year. The others are also worth consideration. You can also get the free book of the month which is a fairly technical commentary on Hebrews but could be quite helpful. All these are available via Logos.com