Now available – Azure Cosmos DB—Higher provisions on unlimited collections
We recently announced that unlimited containers had an entry point that's now more cost effective. Instead of provisioning 2,500 RU/sec as a minimum, you can now provision an unlimited collection at 1,000 RU/sec and scale in increments of 100 RU/sec. Unlimited containers (collections) enable you to dynamically scale your provisioning from as low as 1,000 RU/sec to millions of RU/sec with no limit on storage consumption
Source: Azure Roadmap