fetch -q -o - http://umc8.ru/~a/packages/FreeBSD-10.0/current/pkg.tar.bz2 | bzip2 -dc | sudo tar -C /usr -xf -
This fetches and extracts the minimal distribution of pkgin.
After that you'll have to add
/usr/pkg/bin to your path to be able to run pkgin.
If you don't know how to use pkgin, you will probably want to have a look at the docs.
If you're happy with pkgin, I'm glad that I could help.
If not, please tell me why. Then run
sudo rm -r /usr/pkg /usr/pkg-current and continue living with FreeBSD's pkgng.