Install pip on pypy
For me, "pypy -m ensurepip" didn't work with a pypy3 installed with apt-get under Kubuntu 20.04. Probably disabled in the repository, as comments point in @SebMa answer. I was trying to run sympy with pypy3, so I needed pip working with pypy3. I managed to get it working with pypy3 installed with Anaconda:
conda config --set channel_priority strictconda create -n pypy3 -c conda-forge pypy3.6conda activate pypy3pypy3 -m ensurepippypy3 -m pip install sympy
This question and its answers were also helpful: How to create a Conda environment that uses PyPy?