There are a variety of instance types to choose from when creating a Cortex cluster. If you are unsure about which instance to pick, review these options as a starting point.
This is not a comprehensive guide so please refer to the AWS's documentation for more information.
Note: There is an instance limit associated with your AWS account for each instance family in each region, for on-demand and for spot instances. You can check your current limit and request an increase here (set the region in the upper right corner to your desired region, type "on-demand" or "spot" in the search bar, and click on the quota that matches your instance type). Note that the quota values indicate the number of vCPUs available, not the number of instances; different instances have a different numbers of vCPUs, which can be seen here.
Starting price per hour*
good for dev clusters
high host memory gpu-based
very good price/performance ratio
* on-demand pricing for the US West (Oregon) AWS region.