Display the original and discounted prices

If you are using Woocommerce Groups Pricing, and you need to display the original and the discounted prices, you can add this code in your theme functions.php file.

If you are using Woocommerce 2.5.x


add_filter( 'woocommerce_get_price_html', 'your_own_price_html', 100, 2 );
function your_own_price_html( $price, $product ){
  $result = $price;

  if ( get_option( "wgp-baseprice", "regular" ) == "sale" ) {
    $price_key = '_price';
  } else {
    $price_key = '_regular_price';
  }

  if ( $product->product_type == 'variable' ) {

    $children = $product->get_children(true);

    $original_prices = array();
    $commission = 0;
    foreach ( $children as $child ) {
      $original_prices[] = get_post_meta( $child, $price_key, true );
      if ( $commission == 0 ) {
        $commission = WGP_Variations_Admin::get_commission( $product, $child );
      }
    }

    if ( $commission > 0 ) {
      $min_price = min( $original_prices );
      $max_price = max( $original_prices );
      $original_price = $min_price !== $max_price ? sprintf( _x( '%1$s–%2$s', 'Price range: from-to', 'woocommerce' ), wc_price( $min_price ), wc_price( $max_price ) ) : wc_price( $min_price );
    }
  } else {
    $commission = WooGroupPricing::get_commission( $product );
    if ( $commission ) {
      $original_price = woocommerce_price(get_post_meta( $product->id, $price_key, true ));
    }
  }

  if ( $commission ) {
    $result =  'Was:' . $original_price . " Now:" . $price;
  }
  return $result;
}

If you are using Woocommerce < 2.5.0


add_filter( 'woocommerce_get_price_html', 'your_own_price_html', 100, 2 );
function your_own_price_html( $price, $product ){
  $result = $price;
  if ( $product->is_type( 'variation' ) ) {
     $commission = WGP_Variations_Admin::get_commission( $product, $product->variation_id );
  } else {
     $commission = WooGroupPricing::get_commission( $product );
  }
  if ( $commission ) {
     $result =  'Was:' . woocommerce_price(get_post_meta( $product->id, '_price', true )) . " Now:" . $price;
  }
  return $result;
}