I highly doubt he made more than a few thousands after paying for publishing etc. When his second book was released, e-books were barely making a dent on the internet.
His audience was very, very small compared to other genres and he knew this. Yet Ray went on ahead and published it. This, to me, speaks volumes in that he did it for those who were currently suffering, would suffer, and destined to suffer without having much a say (newborns, kids, preteens, etc.).
Ray Franz has done more to ease the mental suffering of current and former Witnesses than all former member publications put together. Ray just had a rare view into the inner workings and he gave those to us in his brutally honest words. Although, I still believe he could have spewed some really juicy tidbits here and there and confirmed detrimental actions by other GB members and Bethelites, yet he chose not to and this reflects his goal and aim at trying to help the friends and teaching them about how one should truly adhere to Scripture and follow Christ in honor of God.
My only wish, and boy how I wished it, was to speak to him personally. Even corresponding with him would have sufficed.