I didn't know if you are aware that you can get some free ebooks from Ancient Faith. Some are at the Ancient Faith online Store and some are from Orthodox Christian Ebooks (which is part of Ancient Faith).
The books you can get from the Ancient Faith store are:
Orthodox Worship: A Living Continuity with the Synagogue, the Temple, and the Early Church
Know the Faith: A Handbook for Orthodox Christians and Inquirers
The two from Orthodox Christian Ebooks are:
What Orthodox Christians Believe
The one below you need to sign up for texts alerts to get the coupon code. The link for the coupon code
Arise, O God: The Gospel of Christ’s Defeat of Demons, Sin, and Death