There should not be a required amount for someone to preach in any church. This is not a biblical concept by any stretch of the imagination. Read the gospels and the epistles. Paul worked a job so that he would not be a burden to the churches where he evangelized.
2 Corinthians 11:7-8 7 Did I commit sin in [c]humbling myself that you might be exalted, because I preached the gospel of God to you free of charge? 8 I robbed other churches, taking wages from them to minister to you. So they didn't support him but other churches did, they were freeloaders and he let them know.
