How can I list for sell all items in my collection without manually creating a listing for each item?

Joseph.  We don't have a simple link to click to convert a collection into an item for sale, but I think that would be a great idea for us to add.  I'll add it to my list of feature requests.

You should be able to export your collection and then use Excel and our bulk publishing tool to list them all for sale with minimal changes.  You would export, then add a little info to the file to make it work for selling (like the selling price) and then you would upload it for sale.  

I hope that helps for now.