Summary: Paul gives himself as an example of the kind of self control he's talking about. He knows that, as a servant of God, he could rightfully ask for making a living from his ministry. Still, he chooses to serve instead of being served so he can reach more people.
Response: I have similar views on being paid to help lead worship (why should Christmas services be a payday?), but I feel I still lack Paul's zeal for evangelism.