Lock The File — Encrypted Mac vault

Free: up to 5 sealed files
Pro ($29 one-time): unlimited sealed files via license key
Auto-lock when your Mac locks, sleeps, or sits idle
Sold as a macOS app (DMG) with in-app license activation

Customers discover Lock The File through GitHub, Product Hunt, and Mac/privacy communities. They pay a one-time Pro fee through Lemon Squeezy and receive a license key by email.

Support: reply to your Lemon Squeezy receipt email.