What did Paul charge for preaching the gospel? NOTHING!
“What is my reward then? Verily that, when I preach the gospel, I may make the gospel of Christ without charge, that I abuse not my power in the gospel.” 1 Corinthians 9:18
“Have I committed an offense in humbling myself that you might be exalted, because I have preached to you the gospel of God freely?” 2 Corinthians