Microsoft has just announced a series of new service tiers for Azure Search. The previously announced Basic tier has gone from preview to generally available. Azure Search Basic pricing has been increased from the preview price of US$38 per month to $75 / month. Basic supports up to 1 million documents per partition and 5 indexes per service, which is a good option for many small to medium sized web sites.
The new S3 tier is available in preview. It supports storage of up to 2.4 TB of documents, 1.4 billion documents served across 36 scale out units. It is targeted to customers with massive search needs.
Microsoft has also created a tier called S3 HD which is targeted at ISVs and SAAS vendors with lots of customers who have small indexes (e.g. less than 1 million documents). S3 HD allows you to pack in up to 1000 indexes per search service, making it ideal for vendors who need to spin up search instances for many customers.