Because in your ebay store, you can only have fixed price, (buy it now) items. Think of it like a store you would walk into - all the prices are set and you buy something off the shelf. Your auctions will show up in your store, but they are not technically "store inventory". A store is a subscription that you purchase through ebay. It is a place to keep items on a longer term basis. The listings last 30 days.
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