Return a single face from a cube primitive for manipulation

I want to create a cube primitive and scale and re position a single face of the cube while the opposite side stays stationary.

Im sure i can figure out a way to directly manipulate the vertices of the cube, but I was hoping it would be easier to just perform a local scale and position on the entire face instead of worrying about re-positioning each vertex manually.

I would think that the most easy way would be to modify the vertices.

Take a look at my blog post about creating procedural mesh in Unity - that should get you started: