Your app seems like a fairly standard SaaS app. The cost estimate is only "real-time" in the sense that there is some data that is crunched on the server before it's served up to the user. Users just deal with a form and they punch in their data, and then that data is shown to couriers. That's pretty standard CRUD and you don't need anything fancy. Node.js is really cool, but you're going to be a lot more productive and you're going to have a much easier time by sticking to a standard, mature web framework like Django (or Rails).
Are you fluent in Javascript, PHP, or Ruby? If not, that's even more of a reason to stick with Python and Django, because you can literally start learning Django and have your MVP up by Monday.