If an item is out of stock, can I still place an order for it?

If the colour, storage size or grade of a SKU variation is out of stock, the button will be greyed out and you will not be able to click on it or add it to your basket, but you will be able to know the variant exists and what the price is for that SKU variant. 

You will also be able to set up a stock notificaiton for that product by clicking the button "notify when this product is back in stock".  As soon as it is, you will be notified by email immediately - emails are generated at midnight.  You can view all stock notification in your account and you can also turn these off in your account at anytime.

You can only set up a product alert for an entire product if all variations are out of stock.