Q:

How to set zero after Decimal

How to set zero after Decimal 
<?php 
$layer = Mage::getSingleton('catalog/layer'); $category = Mage::getModel('catalog/category')->load($this->getCategoryId()); if ($category->getId()) { $origCategory = $layer->getCurrentCategory(); $layer->setCurrentCategory($category); } $collection = $layer->getProductCollection(); $collection->getSelect()->reset('order'); $collection->getSelect()->order('minimal_price','asc'); $collection->getSelect()->limit(1); 
$cur_code = Mage::app()->getLocale()->currency(Mage::app()->getStore()->getCurrentCurrencyCode())->getSymbol();?>

    <div class="container">

        <div class="row thmub_list">
            <?php
            $catIds = explode(',', $this->getIds());

              $categories = array();
            foreach ($catIds as $catId) {
                $category = Mage::getModel('catalog/category')->load($catId);

    /* new code started */
    //get products from category ID
    $products = $category //Mage::getModel('catalog/category')->load($catId)
     ->getProductCollection()
     ->addAttributeToSelect('*') // add all attributes - optional
     ->addAttributeToFilter('status', 1) // enabled
     ->addAttributeToFilter('visibility', 4) //visibility in catalog,search
     ->setOrder('price', 'ASC'); //sets the order by price

   $largeNumber = 9999999999;
   $minPrice = $largeNumber; //set to higher number 
   $maxPrice = 0;
   foreach($products as $product){
     if($product->getFinalPrice() < $minPrice){
         $minPrice = $product->getFinalPrice();
     }
     if($product->getFinalPrice() > $maxPrice){
         $maxPrice = $product->getFinalPrice();
     }
   }

   if($minPrice == $largeNumber){
       $minPrice = 0;
   }

   //echo "<div>".$minPrice."</div>";
  // echo "<div>".$maxPrice."</div>";

   /* new code finished */

                $categories[$category->getName()] = array(
                    'url' => $category->getUrl(),
                    'img' => $category->getImageUrl(),
                    'minPrice' => $minPrice,
                    'maxPrice' => $maxPrice
                );
            }

            ksort($categories, SORT_STRING);
            ?>        
                <?php if ($category->getIsActive()): ?>
                    <?php foreach ($categories as $name => $data): ?>
                  <div class="col-cxs-12 col-xs-12 col-xs-6 col-sm-6 col-md-4 col-lg-4 custom-item">
                        <div class="panel">          
                            <a href="<?php echo $data['url']; ?>" title="<?php echo $name; ?>" alt="<?php echo $name; ?>">
                                <img id="cat-image" src="<?php echo $data['img']; ?>" class="img-responsive"/></a>
                              <h3 class="product-title"><a href="<?php echo $data['url']; ?>"><?php echo $name; ?></a></h3>
                              <?php $minimum = $data['minPrice']; 
                              $maximum = $data['maxPrice'];;?>
                              <div><?php echo $cur_code . $minimum ?></div>
                              <div><?php echo $cur_code . $maximum ?></div>
                            <button type="button" title="<?php echo $this->__('SELECT BOUQUETS') ?>" class="btn btn-default custom-btn" onclick="setLocation('<?php echo $data['url']; ?>')"><?php echo $this->__('SELECT BOUQUETS') ?></button>     

                        </div>
                  </div>
                    <?php endforeach; ?>
                <?php endif; ?>        
        </div>
    </div>

Now it showing $173.0000

A:

In your case I suggest you use the formatPrice method from Mage_Core_Model_Store
So in your code, assuming that $price contains your original price you can do:
$price = Mage::app()->getStore()->formatPrice($price);

