All economists "are starving artists in comparison to Harvard University’s Greg Mankiw, author of some of the best selling economics textbooks in the country... In 2005, when he stepped down as chairman of President Bush’s Council of Economic Advisers, Mr. Mankiw reported royalties of between $1 million and $5 million on one book alone: Principles of Economics, published by Thomson Learning. He reported between $100,000 and $1 million in royalties on his book Macroeconomics, published by Worth Publishers"
Other salary statistics here. Advising Central Banks seems pretty lucrative too.