SFO-SYD is flown on a 3 class 747. Business class seats are like a first class seat on most other airlines. First class are the completely lay flat bed suites. They are pretty awesome.

For SFO-SYD, the prices are $80 for coach/economy plus, $135 for business, $165 for first class. Of those fares, $35 is tax, and the rest is charged by United. But remember that SFO-SYD is a LONG flight.

SFO-DEN is $14 for coach/economy plus, $24 for first class (or business on the 3 class 777), and $30 for the first class suites. Of that, $7 is taxes. I found it works out to less than 1 penny per mile. Maybe 2 pennies per mile for first class. Pretty good.