“We tried try for 0.0 uh weirdly that is the string that I think hacks your brain to really grock that that button is entirely free 0.0 like 20 decimals.”

"Try for $0.00" Outperforms "Try for Free" — Price-as-Zero Hacks the Brain

Duolingo ran a CTA copy ladder: 'subscribe' to 'start my free trial' to 'try for free' to 'try for $0.00'. Each step lifted conversion, but the explicit-zero format won. Making the price a literal number — even zero — outperforms abstract words like 'free' because it engages the same mental processing used when evaluating any price tag.