Hosting a node costs money. Disk space, CPU power, network traffic cost money. You will pay for them one way or another.
You can install your own server, administer it by yourself and pay for electricity and network traffic. You can rent a VPS, a virtual host (one node instance may handle several domains) or host in a cloud and pay for the rent. Like with regular web hosting, may be costly at the beginning (but not too expensive anyway), but will be cheaper later, at larger scale, as software and hardware improves. Better software also contributes to better hardware utilization.
Moera does not prescribe you how you should get your node. There may exist many service providers and some of them may give you a node for free. This just means that the provider pays the bills and you pay to the provider by giving access to your private data, or by your time and attention when viewing ads, or by using other services which include price of the “free” hosting into their price. It’s your choice - choose what is better to you, just take into account, that “there ain’t no such thing as a free lunch”. If something is marketed as free, it just means you don’t know how, when, and how much you will pay.
Also note that advertising-based services are profitable only at large scale and often closed if they have not enough users. You can remember many Google services that were closed as unattractive, while having millions of users worldwide. A service that takes a fee may be profitable much longer and some of them exist from the early days of Internet. Payment protects you from unexpected discontinuation of the service.
Moera also allows you to profit from your node. Three components: single sign on, subscriptions, and full freedom in giving access to you content to whoever you want make possible to take a payment for subscription or to invent any other business model. And, in contrast to centralized social networks, you will not be blocked or demonetized due to conflict with the social network business model.
There is no “business model of Moera”. Moera is just a family of protocols and software that implements them. Any person or organization participating in the network in any role may take any business approach and profit from interconnectivity and social value that Moera provides.