Because the license for Pine does not allow any binary distribution, Debian, Ubuntu, and probably others make the source package available, but not a ready made binary. To install it, create and cd to a new directory, then:
apt-get source pine apt-get build-dep pine apt-get -b source pine
This has apt download the source for pine, then install any packages needed to build the package, then build (-b) and install it.
NOTE: You may first need:
apt-get install dpkg-dev