Magento has the ability to globally manage inventory levels for your online store. A number of client’s business model was to sell inventory that they picked up from a distributor and therefore didn’t need to manage all items. They did have situations where they purchased items by the case and wanted to to show how many items are left back in stock.
To set and show how many items are left in stock, do the following:
Open app/design/frontend/default/template/catalog/product/list.html (for category page)