Trying to pip install a repo's specific branch. Google tells me to

pip install https://github.com/user/repo.git@branch

The branch's name is issue/34/oscar-0.6 so I did pip install https://github.com/tangentlabs/django-oscar-paypal.git@/issue/34/oscar-0.6 but its returning a 404.

How do I install this branch?

Prepend the url prefix git+ (See VCS Support):

pip install git+https://github.com/tangentlabs/django-oscar-paypal.git@issue/34/oscar-0.6

And specify the branch name without the leading /.