AddFixedPriceItemRequestType ( AbstractRequestType )
This call allows a seller to create and publish a fixed-price listing. The main difference between AddFixedPriceItem and AddItem is that AddFixedPriceItem supports the creation of fixed-price listings only, whereas AddItem supports all listing formats.
Also, only AddFixedPriceItem supports multiple-variation listings and tracking inventory by a seller-defined SKU value. AddItem does not support Variations or the InventoryTrackingMethod field.
Call that uses AddFixedPriceItemRequestType: