There are no instances of tithing in the New Testament. The Apostle Paul collected money to be brought to Jerusalem because the brethren there were having a very hard time, but Paul did not take any of that money. In fact he paid his own way by making tents.
Paul worked and paid his own way while he was preaching the Word of God.
Act 18:3 (CEV) and found out that they were tent makers. Paul was a tent maker too. So he stayed with them, and they worked together.
Act 20:32-35 (CEV) I now place you in God's care. Remember the message about his great kindness! This message can help you and give you what belongs to you as God's people. (33) I have never wanted anyone's money or clothes. (34) You know how I have worked with my own hands to make a living for myself and my friends. (35) By everything I did, I showed how you should work to help everyone who is weak. Remember that our Lord Jesus said, "More blessings come from giving than from receiving."
If we want to support a specific work, we are within our rights to do so. Tithing, though is an expected money and a certain amount. When we tithe to the Lord, it doesn’t not have to be with money. We give our all to the Lord, that includes time, helping out either the Pastor or our brethren in Christ (maybe cooking a meal or cleaning, or praying with them or visiting them—there are many ways this can be done).