One resource for essays about American culture is The Electric Typewriter website, which has a collection, as of 2015, entitled "10 Great Articles and Essays about American Culture." The collection includes "Pell-Mell" by Tom Wolfe, "Fixed Opinions, or the Hinge of History" by Joan Didion and "How to Slowly Kill Yourself and Others in America" by Kiese Laymon.
Many other websites also offer essays on American culture. Example Essays has essays on a huge variety of topics, including American culture, such as "American Culture" and "Native American Culture." However, Example Essays requires an account to read the full versions of some essays.
123helpme.com also offers essays on a wide variety of topics, and over 400 match the term "American culture." A few of the available titles include "The Decay of the American Culture," "Contemporary American Culture and Materialism" and "How Divorce is Affecting the American Culture." Although you can preview any of the essays, almost all of them require payment to be read in full. Prices range, as of 2015, from under $10 to almost $50, depending on the depth and quality of the essay.
A few websites offer just one essay on American culture. AdvancedWriters.com offers a sample piece entitled "American Culture Essay," while TeenInk hosts an essay entitled "American Culture" by laurenmack.