title: How do I change the price string in WooCommerce subscriptions
body: <p>I need a better way to do this.</p>
  
  <p>Currently, I have added code directly to the get_price_string function within class-wc-subscriptions-product.php file, so when a free trial is setup I can change the text being added to the price string.</p>
  
  <p>This, of course, is far from perfect.</p>
  
  <p>So, does anyone know what hook I need to add to the functions.php file in the theme's folder to be able to do the same thing?</p>