Вывод html кода с помощью echo

    $boots = 
    [array("I" => "css/images/1.jpg", "Item Number" => "000001","Size List" => "8/8.5/9.5/10/11","Brand Name" => "Adidas Shoes","Wholesale Price:" => 87), 
     array("I" => "css/images/2.jpg", "Item Number" => "000002","Size List" => "8/9.5/10/11","Brand Name" => "Adidas Shoes","Wholesale Price:" => 77),...]

<ul>
 <li>
  <div class="image">
    <a href="#"><img src="css/images/1.jpg" alt="" width="180" /></a>
  </div>
  <p>
    Item Number: <span>000001</span><br />
    Size List : <span>8/8.5/9.5/10/11</span><br />
    Brand Name: <a href="#">Adidas Shoes</a>
  </p>
  <p class="price">Wholesale Price: <strong>31 USD</strong></p>
 </li>
.
.
.
</ul>

<?php 
     for ($i=0; $i < sizeof($boots); $i++) {
        foreach ($boots[$i] as $key => $value) {
            echo '
                <li>
                    <div class="image">
                        <img src="$value" alt="" width="180" />
                    </div>
                    <p>
                        $key: <span>$value</span><br />
                        $key : <span>$value</span><br />
                        $key: <a href="">$value</a>
                    </p>
                    <p class="price">$key: <strong>$value USD</strong></p>
                </li>';
        } 
    }
?>

Для генерации HTML удобно использовать альтернативный синтаксис PHP.

<ul>
    <?php foreach( $boots as $boot ): ?>
        <li>
            <div class='image'>
                <img src="<?= $boot['I'] ?>" alt="" width="180" />
            </div>
            <p>
                Item Number : <span><?= $boot['Item Number'] ?></span><br />
                Size List : <span><?= $boot['Size List'] ?></span><br />
                Brand Name : <a href=""><?= $boot['Brand Name'] ?></a><br />
            </p>
            <p class="price">Wholesale Price: <strong><?= $boot['Wholesale Price:'] ?> USD</strong></p>
        </li>
    <?php endforeach; ?>
</ul>

<?php 
  foreach ($boots $value) 
  {
    echo '
      <li>
        <div class="image">
          <img src="'.$value['I'].'" alt="" width="180" />
        </div>
        <p>
          Item Number : <span>'.$value['Item Number'].'</span><br />
          Size List : <span>'.$value['Size List'].'</span><br />
          Brand Name : <a href="">'.$value['Brand Name'].'</a>
        </p>
        <p class="price">Wholesale Price : <strong>'.$value['Wholesale Price'].' USD</strong></p>
      </li>';
  } 
}
?>

Если так, то

echo '
                <li>
                    <div class="image">
                        <img src="' . $value .'" alt="" width="180" />
                    </div>
                    <p>
                       ' . $key .': <span>' . $value . '</span><br />
                        ' . $key .': <span>' . $value . '</span><br />
                        ' . $key .': <a href="">' . $value . '</a>
                    </p>
                    <p class="price">' . $key . ': <strong>' . $value .' USD</strong></p>
                </li>';