Here are some deals that free for the month of July.
Logos – For July, Logos is giving out ‘The Righteousness of Faith according to Luther’ by Hans J. Iwand.
Ligonier – ‘Jesus the Evangelist: Learning to Share the Gospel from the Book of John‘ is free for this month. This is a good book to read if you want to see how Jesus does evangelism in the gospel of John
Desiring God – T.H.L Parker’s biography of John Calvin (only for 10th July)
I’ll add more if I see more deals for this month, so do check back often!