| Clue | Source | Date |
|---|---|---|
| Sort of pricing model with multiple tiers | New York Times | 31 May 2019 |
| Sort of pricing model with multiple tiers | ||
| Pricing model for many apps | New York Times | 08 Oct 2016 |
| Pricing model for many apps | ||
| Business model in which only the deluxe version of a product costs money | ||
| Modern-day business model offering partial complimentary goods |