Blender is great for making the mesh. It's free and there are plenty of tutorials on YouTube.
Export the Blender mesh as an .obj file.
Open the obj file with Pepakura Designer and unfold it.
OK, it's not quite as easy as all that. I'm just pepping a Dredd 3D helmet and I'm on version three, just assembling the pep file for fine tuning the dimensions in the major axes, then it's back to (hopefully) the final version after I've modified the mesh with Blender.
Buy Pep designer - it's great value for money and very user-friendly. Blender is free and these days there are tons of different tutorials.