There is an an out of stock report in the "Reports" area of the Content Management System shopping cart so that you can quickly determine which products are low in stock.
You can set the Availability Format for both the Category / Product List pages and Product detail pages separately.
Note: When you change a product availability listing, it changes the order of the product but not the product description. Make sure to enter "Sale Item" (or whichever info relates to the priority listing) in the Product Title or Product Description fields.