I see this in a slighlty different way: the worker deserves his wages. Now, let us suppose that it costs $6.00 to produce a study Bible, from the rights to a translation to the shipping of the final product. The Company feels that it needs to make at least $6.00 on it to stay afloat. The bookstore then pays $12.00 for it and sells it for 19.95 regular price, less on sale. I have no issue with that. My issue comes in with what people DO with the money that they make off of religion.
Years ago, before the fall of the televangelists, Jimmy Swaggart had a $800,000 wall around his house. There are other examples. So many people make money off of religion and then do not use it to help others. There is the issue.
It has been pointed out that the author of a Purpose Driven Life, Rick Warren, uses 10% of the money from his works to live on and give 90% to various ministries. I would dare say that he is the exception. Here in Alabama, I see folks who are ministers driving $70,000 cars given to them by their churches. Some of the larger churches pay in excess of $100,000 per year. Ok, fine, that is the choice of that church. I would ask how would Jesus see this.