You get one. The extra cost is due to the built-in Activesofts that come with it.
You buy one to have a pet camera follow you around and record your life for your liveblog.
You buy three, and take the professional upgrade package, if you want to do some quality Trideo shooting, with over-to shots and the like, with one on you, one on the interviewed person, and a third set up to show the both of you and the set, pivoted around to show scenery (You set up a nice AR screen, right?) and so on.
The single CU^3, with the pro upgrade, is perfect for a spunky reporter to have with them after she hires your team to break into some corporate facility where she can film Shenanigans... the drone does most recording when she wants to be on screen, but her handicam is also used as a back-up.
Otherwise, you'll find several young people walking around the street with them, recording their ongoing monologue, making sure that we all see what they get for lunch or where they shop, and so on. And, you know ... annoying old people. Can't put a price on that!