If your amazon item shows a $0 price, likely that item is what Amazon has called "stranded" or "restricted." Amazon will still fulfill these items if you sell them on a different marketplace, so you can still list these items on eBay using JoeLister. However, if there are no other sellers for this item and no listing on Amazon, JoeLister won't be able to automatically make the listing "beautiful" for you.
You can find all these stranded items by unchecking all the categories in the "show items" box except for "Stranded."
If it's still not showing up, please see the update below.
Stranded inventory can be fixed through Amazon by following the instructions here:
We just added a new feature at the bottom of the "Advanced Settings" pages of premium accounts (any plan above Basic). This feature will let you upload a CSV of your stranded items so JoeLister knows which ones to properly import. There's lots of strange identifiers on stranded items that makes them hard to differentiate from other items, which is why we needed to make this update. After you've imported your stranded SKUs, please click "Update Inventory" on your Amazon Inventory page and wait for the update to complete. Then, make sure you have the appropriate view settings selected and search for your stranded inventory again! They should appear then. If this does not work, it may not be possible to list this particular item. See this article for more detail on how it works!