You are paid in cash at the field by the teams. With very few exceptions, USSF uses the three referee system (one referee + two assistant referees).
High School matches
High schools pay by check, usually presented to the official at the field, but sometimes sent to their homes a few days later.
Through spring 2008, the fees are a flat fee of $35 for JV and $45 for varsity.
A Note About Taxes
All GLASRA referees are "independent contractors," and are "self-employed" for tax purposes. As an independent contractor, you are always responsible for paying any taxes owed to federal, state or local government for compensation received as a soccer official. Consult a reliable tax expert if you have questions about paying taxes on income made while officiating soccer.