I am working on mac OS X Yosemite, version 10.10.3.
I installed python2.7 and pip using macport as done in http://johnlaudun.org/20150512-installing-and-setting-pip
In addition to adding python's bin directory to $PATH variable, I also had to change the owner of that directory, to make it work. No idea why I wasn't the owner already.
bin
$PATH
chown -R ~/Library/Python/