无法在opencart中显示价格

Question

I've customized opencart v.2.0.3.1 and now there is a problem: in Admin page I add a price and everything is fine.

But when I want to see price in Product page there is no price at all

Can someone tell me how to fix this problem?

and this is the code

<div class="box_style_1 expose <?php echo $class; ?>" >
        <h3 class="inner">Add to cart</h3>
        <h2><?php echo $heading_title; ?></h2>
        <ul class="list-unstyled">
          <?php if ($manufacturer) { ?>
          <li><?php echo $text_manufacturer; ?> <a href="<?php echo $manufacturers; ?>"><?php echo $manufacturer; ?></a></li>
          <?php } ?>
          <li><?php echo $text_model; ?> <?php echo $model; ?></li>
          <?php if ($reward) { ?>
          <li><?php echo $text_reward; ?> <?php echo $reward; ?></li>
          <?php } ?>
          <li><?php echo $text_stock; ?> <?php echo $stock; ?></li>
        </ul>
        <?php if ($price) { ?>
        <ul class="list-unstyled">
          <?php if (!$special) { ?>
          <li>
            <h2><?php echo $price; ?></h2>
          </li>
          <?php } else { ?>
          <li><span style="text-decoration: line-through;"><?php echo $price; ?></span></li>
          <li>
            <h2><?php echo $special; ?></h2>
          </li>
          <?php } ?>
          <?php if ($tax) { ?>
          <li><?php echo $text_tax; ?> <?php echo $tax; ?></li>
          <?php } ?>
          <?php if ($points) { ?>
          <li><?php echo $text_points; ?> <?php echo $points; ?></li>
          <?php } ?>
          <?php if ($discounts) { ?>
          <li>
            <hr>
          </li>
          <?php foreach ($discounts as $discount) { ?>
          <li><?php echo $discount['quantity']; ?><?php echo $text_discount; ?><?php echo $discount['price']; ?></li>
          <?php } ?>
          <?php } ?>
        </ul>
        <?php } ?>

</div>