Sliding scale in Excel 2003 (Difficult)

Hello,

I need a sliding scale formula with which I'm having difficulties. Below is the data.

Anything under $100,000 will get a commission of 10%

Over $100,000:

Bracket:

0-100,000 - 8%
100,001-500,000 - 6%
500,001-999,999 - 4%
1,000,000-3,000,000 - 2%

Thank you.