A servant of God is one who expresses submission to perform services for free. So that when a servant is accepting a fee for services rendered then he is more of a businessman treating the word of God as a merchandise for sale.
Luke 17:7-10 But which of you, having a servant plowing or feeding cattle, will say unto him by and by, when he is come from the field, Go and sit down to meat? And will not rather say unto him, Make ready wherewith I may sup, and gird thyself, and serve me, till I have eaten and drunken; and afterward thou shalt eat and drink? Doth he thank that servant because he did the things that were commanded him? I trow not. So likewise ye, when ye shall have done all those things which are commanded you, say, We are unprofitable servants: we have done that which was our duty to do.
It is therefore a must for all servants of God to preach the gospel for free making this calling to serve as unprofitable.
2 Corinthians 11:7 Have I committed an offence in abasing myself that ye might be exalted, because I have preached to you the gospel of God freely?
Such were the apostles of Christ compared to pastors, priests and preachers of today who are receiving money as payment, call it stipend, allowance, complimentary, accommodation or whatever, it's the same banana.