Databases are billed based on time consumed. You are not billed for an entire month unless your database is provisioned that entire time. Pricing varies based on the instance you provision, the amount of storage, and the region you provision in. Below you will find the pricing by instance size for the East region of both AWS and Azure.

Hobby Tier Cores Memory Max IOPS Price/month
Hobby-2 1 2GB 11,800 US$35.00
Hobby-4 1 4GB 11,800 US$70.00
Hobby-8 2 8GB 11,800 US$140.00
Hobby-16 4 16GB 15,700 US$280.00
Standard Tier Cores Memory IOPS Price/month
Standard-8 2 8GB 18,750 US$140.00
Standard-16 4 16GB 18,750 US$280.00
Standard-32 8 32GB 18,750 US$560.00
Standard-64 16 64GB 18,750 US$1,120.00
Standard-128 32 128GB 30,000 US$2,240.00
Standard-192 48 192GB 40,000 US$3,360.00
Standard-384 96 384GB 60,000 US$6,720.00
Memory-optimized Tier (AWS only) Cores Memory Max IOPS Price/month
Memory-16 2 16GB 18,750 US$240.00
Memory-32 4 32GB 18,750 US$480.00
Memory-64 8 64GB 18,750 US$960.00
Memory-128 16 128GB 18,750 US$1,920.00
Memory-256 32 256GB 30,000 US$3,840.00
Memory-512 64 512GB 60,000 US$7,640.00

High availability is available on all tiers and increases your cluster price to twice the amount per month.