title: How to get applied coupon amount in woocommerce?
body: <p>I am trying to add a special discount when my cart subtotal is 0. This discount will be applied on cart total which include shipping charges.</p>
  
  <pre><code>function add_discount_line( $cart ) {
      global $woocommerce;
  
      if($woocommerce-&gt;cart-&gt;get_applied_coupons() &amp;&amp; $cart-&gt;subtotal==0){
  
    $discount = 2; // here I want the amount of applied coupon
   $cart-&gt;add_fee( __( 'Special Discount', 'woocommerce' ) , -$discount );
  }
  }
  add_action( 'woocommerce_cart_calculate_fees', 'add_discount_line' );
  </code></pre>
  
  <p>$discount = 2; // How I can get the discount amount of applied coupon here.</p>