Okay, thanks a lot to Peter Wood for linking me to the right version of pypy.
Here's what I did to get it up and running on my pi (noob friendly guide :p):
Step 1: Download .tar.bz2 file using:
wget https://bitbucket.org/pypy/pypy/downloads/pypy3-v6.0.0-linux-armhf-raspbian.tar.bz2
Step 2: Extract the .tar.bz2 file:
tar xf pypy3-v6.0.0-linux-armhf-raspbian.tar.bz2
Step 3: cd into the newly extracted directory:
cd pypy3-v6.0.0-linux-armhf-raspbian.tar.bz2
Step 4: cd into the bin directory and check if the pypy3 executable works:
cd bin
./pypy3 # This should start the pypy interpreter for you
If the last command does not work, make sure pypy3 has execute permissions! (it should be green when you view it with ls). You can give it execute permissions using:
sudo chmod +x pypy3 # But you have to be in the /bin directory!
You may also get a libffi.so.5: No such file or directory error, to fix that I used:
sudo ln -s /usr/lib/arm-linux-gnueabihf/libffi.so.6 /usr/lib/arm-linux-gnueabihf/libffi.so.5
Now we want to set this up so that simply typing pypy3 from anywhere will invoke this interpreter. Here's how we can do that.
Step 5: Move the folder to /opt/
sudo mv /home/pi/pypy3-v6.0.0-linux-armhf-raspbian/ /opt/
Step 6: Add symbolic link to /usr/bin/ by running:
sudo ln -s /opt/pypy3-v6.0.0-linux-armhf-raspbian/bin/pypy3 /usr/bin/pypy3
Okay, now cd out of there and run pypy3 from any location, it should invoke the pypy interpreter! Hope this helps :)