Don’t we all wish the self employment tax was some kind of flat $400 fee!
That’s not it at all. Self employment tax in the US is the Social Security and Medicare tax that is normally half-paid by the employer and half-paid by the employee. When you don’t have an employer, you must pay the entire total yourself as self-employment tax on Schedule SE.
The 2006 rate is 15.3% percent for income up to $94,200, and 2.9% on all income above that.