Making your own soup is immensely satisfying - not only do you know exactly what's gone into it, it frequently tastes better than commercially produced soup. And it's usually cheaper too! So why not make your own pea and ham soup - you'll be glad you did.
By the way, I say here that you can use ham hock or shank, and you may be wondering what the difference is. Well, it seems the hock is the bit of the pigs leg directly above the trotter, and the shank is a bit further up than that. The shank has more meat on it.