I have friend who is a sub 4 miler, was getting around 10k base salary a year from Saucony.
A 28:00-28:30 guy gets something similar.
Time bonuses and place bonuses at major races are usually a big part of a runners contract and if you have good year you can do pretty good.
I know guys like Teg and Solinsky signed pretty good contracts right after college that didn't require them to work a "real" job (though I'm not sure how much).