Fake it to learn it.
A prototype is a question in disguise. Pick the cheapest one that answers the question you actually have.
The Fidelity Ladder · Climb Only When You Need To
Minutes
Sketch
Does the concept make sense to anyone?
Hours
Clickable Mockup
Can people find their way through the flow?
Days
Wizard Of Oz
Looks real, but humans do the work behind the scenes. Is it valuable?
Weeks
Concierge
Do it manually for a few customers. Will they rely on it?
Source: OpenClassrooms ↗
Cheapest test that answers the question.