If I want to use the pip command to download a package (and its dependencies), but keep all of the zipped files that get downloaded (say, django-social
pip wheel is another option you should consider:
pip wheel mypackage -w .\outputdir
It will download packages and their dependencies to a directory (current working directory by default), but it performs the additional step of converting any source packages to wheels.
It conveniently supports requirements files:
pip wheel -r requirements.txt -w .\outputdir
Add the --no-deps argument if you only want the specifically requested packages:
pip wheel mypackage -w .\outputdir --no-deps