Printers' Ink, Feb 24, 1927 (Vol. 138, No. 8): "Why I Do Not Charge for Samples: A Reply to Norman Lewis" by Claude C. Hopkins
The pattern
This still sits in the public-domain pool. No pattern name yet.
Why it works
Claude Hopkins explaining why free product sampling outperforms charged trials. Giving full-sized samples without cost allows products to prove themselves, accelerating mass customer conversion.
Steal this when
When deploying unconditional free product sampling to accelerate mass market customer trial.