Hey there – Are you creating an Item and a Variation? See our quick walkthrough here for an explanation. Variations are the actual “thing” being sold, and is considered a sub-set of Items.
When you create an item through our dashboard or mobile app, we automatically create a variation called “Regular” for you.
An item needs a variation before it will show up in the dashboard, so you will need to include (or add later) a variation to see it show up. An item itself can’t be sold as mentioned by @wiggins above; a variation is required.
I actually don’t think there is a way to do that unfortunately. I think this is tied to the ecom_available field, which is read-only at this time and can’t be set by the API.