We have various types of plans: Tier 1, Tier 2, Tier 3. Of course have free trial too!
The differences among plans are custom domain supported, number of site you can host, storages and data transfers.
Checkout the details on the following documents:
You can find Key features on Shifter Key Feature.
How to create WordPress site and make it public on Creating a new WordPress site.
Our WordPress container specs is here: Shifter Container Specs
We're always welcome your feedback for new features or fixes.