It's gonna vary from one part of the USA to the next, but according to the 2001/02 Salary study...
Beechjet 400 SIC, start out around $30,000 to $35,000
High pay would be $45,000 to $50,000, low pay $25,000...
Never flew a Beechjet, but I flew a CE-560 and starting pay on that piece of equipment was $34,000 for an operator in the Southwest USA.
But keep in mind that most pilots will bust their first year salary, everyone I personally know has.
I made exactly $40,000 my first year, but we were flying 60 to 70 hrs a month.
Many factors will go into your potential earning power above your base salary. Unless you are locked in on a hard pay scale by your employer and not paid by the flight hour.
We are paid per flight hour as well as away from base pay.
Sheik