[rayrutjes]

(n.b: I am an engineer at Algolia) Algolia's engine computes relevance at indexing time by design, allowing us to deliver optimal search performance at query time. As a result, each new `sort` - by price, by name, by date added - requires several indices containing identical data.

To make this easy to implement, we provide a way to create index replicas, read-only indices that can have different settings from the master index.

When using replicas, every record added to a master index gets also added to the replica index. Same goes for deletion and update operations.

All indexing operations done on replicas are not billed.

By using replicas, you can adjust your calculate by removing the factor of four you included for each index, meaning that 300K*30 days = 9million operations/month. This assumes you update the entire index daily, whereas you could also only update the prices that changed, which would in turn further reduce the number of operations.