title: Magento 2: Switch the price for 'Sold' label after product is out of stock
body: <p>I'm trying to to switch the price for a 'Sold' label on the product page of products that are out of stock.
  If a product is sold out, the price should be hidden and in its stead should be a 'Sold' label.</p>
  
  <p>I figured out that the price is placed in catalog_product_view.xml and it calls upon the <code>vendor/magento/module-catalog/view/base/templates/product/price/final_price.phtml</code> file, but I could not figure out where and how to bring in a condition to check whether product is sold out or not.</p>
  
  <p>Can someone help here?
  Thanks in advance.</p>
  
  <p>Yuan</p>