#. Go to *'Sale > Catalog > Product'*.
#. Set *Show inventory on website and allow sales if not enough stock* in
   inventory availability field.
#. You can set a custom message that appears when available stock is less than
   0.0 units.
#. Go to Website Shop.
#. Click in any product that you know that no stock available.
#. You will see '*0 units in stock*' but you will buy this product.