How much can a self employed married man earn before paying tax wife not working wife not working?

A self-employed person must file an income tax return and pay self-employment taxes on net income from self employment of $400 or more. As for federal income tax, assuming that you have no children and do not itemize, you can earn up to $17,900 (the sum of two personal exemptions and the standard deduction for married filing jointly for 2008) of net self-employment income before income taxes will apply.