This museum participates in the Bank of America Museums on Us program. On select weekends, Bank of America customers get free admission to the museum. I was delightfully surprised the last time I dropped by and admission ended up free for me and my boyfriend.
Info at: http://museums.bankofamerica.com/
On a more relevant note, this museum is awesome. Really great contemporary art collection. This museum has a photograph by Vic Muniz, from his project he did in collaboration with workers at one of the world's largest landfills in Brazil. This project was the topic of Wasteland, an AMAZING documentary that was nominated for an Oscar. I thoroughly enjoyed seeing the photograph at the PAM after watching the documentary. Good times.
PS: The cafe on site is not very good. They don't even have an espresso machine. If need be, I would recommend getting coffee beforehand or afterwards.