Starting in April 2022, you can set autoscale with a maximum RU/s as low as 1,000 RU/s (scales between 100 RU/s and 1,000 RU/s). You also can set a scale range of 200 RU/s to 2,000 RU/s or 300 RU/s to 3,000 RU/s. Previously, the entry point was 400 RU/s to 4,000 RU/s.
We recommend this configuration for workloads that have low throughput requirements, but which still might scale to the maximum RU/s.