What to do in the first ten minutes
Leave Amplitude exactly where it is if it is already installed. Add the Tiny Funnel script tag next to it, then open the recorder and click through your own signup the way a customer would: the landing page, the pricing page, the signup form, the welcome screen. That click-through is the funnel. There is no taxonomy meeting first and nothing to name.
If the last step of your funnel finishes on a server rather than in a browser, a subscription webhook or an invoice paid on a schedule, post it as a server event with your own user id and it lands on the visitor who caused it, next to everything they did on the way there.
Amplitude is where a company arrives, not where it starts
Amplitude's own pitch has widened over the years: behavioural analytics, experimentation, session replay and a customer data platform, sold as one unified product. That breadth is real and a lot of it is genuinely good. It is also arithmetic, not incompetence: every product added is another concept the interface has to carry, and every concept is something somebody has to learn before the tool answers a question.
Our reader is usually not at that point yet. They have one question this Tuesday afternoon, where did these people come from, how far did they get, and who actually bought, and the honest answer is that Amplitude can tell them, once the taxonomy exists to ask it with. How per-event pricing changes what gets recorded is the same mechanism from the billing side: when an event costs money, you decide what is worth tracking before you know what you will want to ask, and the taxonomy tax shows up twice.
The short version
Keep Amplitude for the day a product org needs behavioural depth and has someone to run it. Use this for the funnel question today: one script tag, a click-through, and a live funnel in minutes. They can run side by side, and disagreeing on the numbers is information, not a bug.