"334" by Thomas Disch. Hardly sf at all.
Also "The Space Merchants" by Pohl & Kornbluth. Might be too "sci-fi" for you though, as it presents a nightmare future in which corporations and manipulative advertising have taken over society, and we all know that couldn't happen, right?
Then there's that OTHER Edgar Pangborn post-apocolyptic novel, "Davy," which is so light and happy that it hardly qualifies as dystopian, despite the setting. It almost makes you wish you could be lucky enough to live in such a world.