Oregon:

6A/5A/4A Varsity - $48 ea Ump
3A/2A Varsity - 43.25 ea Ump
6/5/4 JV - 38.50 ea Ump (increase by 1/3 if you work it alone)
6/5/1 Freshman - 33.50 ea Ump (increase by 1/3 if you work it alone)

Playoffs, add $5 per ump (all 3 man)
State Championship game, add $10 per ump (all 3 man)

In my association, we have negotiated to get 1 round trip milage at $.44.5 per mile, calculated from downtown Portland to the school. This total is split by how many umpires work the game.