Stay tuned for that :). RelationalAI is developed as a multi-tenant service that has a pay-as-you-go model. This should make it possible for everybody to use the product. I expect we will have some free tier options too, but we have not decided on the exact model for that yet. We are starting to onboard individual preview users already.

We're good friends with Materialize.io and use similar techniques for general incremental view maintenance, but their product is quite a bit different: their purpose is to design for SQL. RAI offers a different programming model to capture complex application and business logic (the language for that is called Rel, and docs are public).