What are the four service startup types?

The four service startup types are:

1. Freemium - Offering a basic service for free while charging for premium features.
2. Subscription - Charging customers a recurring fee for continuous access to a service.
3. Marketplace - Connecting buyers and sellers, typically taking a commission on transactions.
4. On-demand - Providing services as needed, often through an app or platform, allowing for immediate access.