Instance store and EBS are both block storage options from AWS. So, what’s the difference?
Instance store volumes are actually attached to the EC2 host machine. Because of that physical connection, instance store provides the lowest-latency among all storage options. However, the data here is ephemeral: I do not recommend using instance store for production data. Moreover, only certain instance types can have instance store volumes. If the instance type offers it, you pay no extra cost for instance store.
EBS volumes are network-attached. Despite data having to travel over the AWS network, EBS still gives you low-latency. The data is persistent: even if your instance stops, your data remains just like data in a hard drive. Moreover, you can detach and re-attach EBS volume to any number of EC2 instances. EBS also incurs its own costs, in addition to the EC2 costs.