The lesson
Prove demand with a physical exhibit from your own field research, such as a receipt, instead of asserting it.
In this deck rebuilt by Pitch Unfairly, Ruth Handler pitches Barbie. A table puts an "Ours" column, marked "PENDING APPROVAL", beside baby doll, paper doll and Lilli. Next, a "Sales slip" from Switzerland, 1956, lists three Lilli dolls under an "EXPENSE REPORT PENDING" stamp, beside "Europe already sells her. I bought three."
The 1950s doll story and the $3 price are the case's own. Keep the exhibit-per-claim habit and the "who buys, who gates, who uses" split.