Prebuilt binaries for Windows OS (both 32 bit and 64 bit) are available on http://www.wxpython.org/download.php page. Latest versions of installers available are − wxPython3.0-win32-188.8.131.52-py27.exe for 32-bit Python 2.7 wxPython3.0-win64-184.108.40.206-py27.exe for 64-bit Python 2.7
wxPython demo, samples and wxWidgets documentation is also available for download on the same page.
wxPython binaries for many Linux distros can be found in their respective repositories. Corresponding package managers will have to be used to download and install. For instance on Debian Linux, following command should be able to install wxPython.
sudo apt-get install python-wxgtk3.0
Prebuilt binaries for MacOS in the form of disk images are available on the download page of the official website.