It will truly depend on the organization. Some churches don't have a paid Youth Leader/Pastor. They have only volunteers. Many however require more time and therefore it is necessary to hire one. I was the Director of Religious Education of our parish/church but I also volunteered as the Youth Leader. I was paid to be the DRE but not the Youth Leader. It didn't require as much of my time. We however were a smaller church, about 950 families. I know of much larger parishes that have paid Youth Ministers and they tend to work under the DRE. The amount they are paid will also depend on the size and location of the church. I made a salary but some employees made hourly wages. It will depends on the educational requirements and duties preformed for the position. But remember churches are non-profit and no one makes much. It's a labor of love. Part of our sacrifice for God. I was paid just enough to pay for my children's private school education and a little left over. And I loved every moment of it. Do what you love and the money will not be AS important. Money is important but being happy in what you do is so valuable. If, like me you are fortunate to have a spouse that makes enough so that you don't have to worry, then it's worth it no matter how small the pay. Speak to your particular pastor about what is required for the job at your church and what the average pay is for that job. Then decide if that's something you want to pursue. There aren't many jobs out there for this particular field. We tend to stay till retirement. It's that fulfilling.
It will vary on several factors like the size of the church, where you live, etc. Here is a good article on it if you want to read more: