...And why the price differential?
When a node is a Shared node. E.g Launching an Aion node:
It means you are sharing a cloud server with others as your node for connecting to the Aion network (fully encrypted, of course). The reason it's less expensive is that in sharing the cloud server across multiple customers it reduces costs for Blockdaemon, which we then happily pass the savings back to you.
If you choose AWS or GCP you get your own discrete node to connect. This adds a layer of security and privacy which may appeal to the enterprise user, but also a bit more expensive.
As always, come chat with us (Live!) if you have more questions.