[wire2john]

Even worldly teenagers know that when you go on a road trip with friends everybody should pitch in for gas if they have some money; its just instinctively fair and to fail to do so would mean you are probably not a true friend. The same principle applies to the church today. We are all friends here, or should be, so if you can help pay for the costs associated with the group you are traveling with, do so! Don't hide behind a "10% rule", give what you know YOU can give and don't worry about what your neighbor is doing; he will answer for himself in due time.
There will also be times when God will impress upon you to give a certain amount without anyone else knowing anything about it. I don't have to tell you what you should do in those situations.