A typical approach to youth ministry (I think):
A. Start with a part-time (or volunteer) position, and see how it goes.
B. Add staff – interns, secretary, associate, worship leader, Jr. High guy, etc. – as you grow in size.
This investment strategy makes sense, because much youth ministry is audience-based. The primary focus is the “audience” already coming to our church (or other youth effort). Those kids need to be discipled, and the amount of work is fairly directly proportional to attendance size.
So… A small initial investment, growing ad infinitum to get the job done.
Many groups and churches try to invest in college ministry this way, too. But are college ministry and youth ministry similar enough?
(We staff a lot of ministries that way; youth ministry is just an example.)