Personally I have no issue with purchasing books, CD’s or other items from Christian authors, ministers, etc....After all its not produced without cost nor effort so a $$ transaction is no biggie. However purchasing a product from a minister or church that practices an overly lavish lifestyle is definitely cause for refrain.
This is where the discernment given by the Holy Spirit and study of the Scriptures comes in. If someone claiming to be a "Christian" teaches something that is in total opposition to the word of God, then we know that they are the "wolves in sheep's clothing" the Holy Spirit warned us about.
Unfortunately, many desperate and lonely and vulnerable people are taken in by these people and can lose every penny they have. And if you notice, those are the exact people who are targeted with promises of healing and help with wayward children and an end to financial problems.
The Paul and Jan Crouches of the world are despicable.