Grumble.... I agree that God doesn't need your money to complete his ministry, but he does want it and he uses it.
I will skip all the verses about the importance of giving (unless you want to hear them) except for two sets:
2 Corinthians 9:7 KJV
Every man according as he purposeth in his heart, so let him give ; not grudgingly, or of necessity: for God loveth a cheerful giver.
Philippians 4:16-18 KJV
For even in Thessalonica ye sent once and again unto my necessity. [17] Not because I desire a gift: but I desire fruit that may abound to your account. [18] But I have all, and abound: I am full, having received of Epaphroditus the things which were sent from you, an odour of a sweet smell, a sacrifice acceptable, wellpleasing to God.
What I want to point out is that 1. We are not to give out of necessity and 2. While preachers (like Paul) have a use for it, giving is more beneficial to YOU the giver than it is to the preacher.
Now, Paul used the money given to him to travel and spread the gospel, but he also used it to give relief to the Church at Jerusalem. So, those that gave were blessed, Paul was blessed, those that heard him in a new town were blessed and the Church at Jerusalem was blessed because there were Holy Ghost filled givers.
I understand folks being grumpy about radio and televangelists asking for money... They seem to be businessmen instead of servants of God. It makes you wonder if they see it as a career instead of a calling. I get that! But if they are honest, look at it from their POV. Some of them put a lot of effort into putting together meaningful sermons and depend on help continuing their ministry. Yet, they get sideways looks from their congregation when they talk about giving.