It uses:
- Netlify's free tier for the homepage + Netlify CMS (free) for content editing
- Firebase within the free limits for cloud functions, storage + user authentication
- The free tier of Crisp web chat for support
- The Chrome store which hosts the extension for free ($5 sign up fee)
- Paddle for payments. They take a % of each transaction but they don't have a sign up fee or ongoing fees.