You don’t always get what you pay for. That’s one of the key messages in Raj Patel’s new book, “The Value of Nothing: How to Reshape Market Society and Redefine Democracy.’’ Patel points out the difference between price tags and actual value, along with the political, environmental, and social costs of the stuff we buy and consume. The author/activist also offers ideas for solving current economic problems and creating sustainability. He talks about his new book with National Public Radio’s “On Point’’ producer John Wihbey. 6 p.m. $5. Brattle Theatre, 40 Brattle St., Cambridge. 617-661-1515, www.harvard.com
Because events can always be canceled or sold out, it’s best to call to confirm. Send event information two weeks in advance to jwulff@globe.com (please include event date in the subject line). 
