Sbort Answer
There is none. It doesn’t take much to run a website (hosting, that’s about it). We receive book royalties of a few hundred dollars a year that cover the costs.
Long Answer
Dr. Aiken has never received funding from the pharmaceutical industry. He is the editor-in-chief of the Carlat Psychiatry Report, which is one of few medical publications that does not accept advertising or industry funding (this website is another one).
Dr. Phelps used to speak about bipolar disorder on behalf of the pharmaceutical industry but gave that up in 2008 when they wanted him to talk about their drugs. He hasn’t accepted industry funding since then.
(updated 11/2020)
Jim Phelps 
Chris Aiken