I'm no great piper myself but I dabbled in it 5 years ago. I need to get back into it but I just don't have the time to make the commitment to it.
Ok, so now that we've established my limited credentials, let me suggest that you start with a chanter alone. Save the money you would have spent on the beginners pipes till later. Or use it to get some lessons if you don't have a pipe band nearby to learn from or you don't wish to play in a pipe band.
I know several talented pipers and all of them still have their chanters. They're dead useful to practice on, because they're easier to carry around, there's less going on with them and they're quieter (believe me, that's important when you're making your first squeaks). Let other more qualified members weigh in, but I'd say to just start with the chanter.