Exclude sample product from “starting at” minimal price

Question

Im trying fo find a solution to manage this. I have an item on every grouped product with a low value (5 dollar) witch is a sample of the main product.

I like to exclude the samples from minimal price calculation on category view (Starting at:) The sample item can be identified with SKU = "****SAM" or by name = "*** Sample"

Later i like to set samples free for wholesale (0.00) and would also like to exclude them from minimal price listing Starting at:

Here the code of /template/catalog/product/price.phtml How can i exclude grouped item who has "SAM" in SKU or "Sample" in name from minimal price calculation please.

 <?php if ($this->getDisplayMinimalPrice() && $_minimalPriceValue && $_minimalPriceValue < $_product->getFinalPrice()): ?>

    <?php $_minimalPriceDisplayValue = $_minimalPrice; ?>
    <?php if ($_weeeTaxAmount && $_weeeHelper->typeOfDisplay($_product, array(0, 1, 4))): ?>
        <?php $_minimalPriceDisplayValue = $_minimalPrice + $_weeeTaxAmount; ?>
    <?php endif; ?>

    <?php if ($this->getUseLinkForAsLowAs()):?>
    <a href="<?php echo $_product->getProductUrl(); ?>" class="minimal-price-link">
    <?php else:?>
    <span class="minimal-price-link">
    <?php endif?>
        <span class="label"><?php echo $this->__('As low as:') ?></span>
        <span class="price" id="product-minimal-price-<?php echo $_id ?><?php echo $this->getIdSuffix() ?>">
            <?php echo $_coreHelper->currency($_minimalPriceDisplayValue, true, false) ?>
        </span>
    <?php if ($this->getUseLinkForAsLowAs()):?>
    </a>
    <?php else:?>
    </span>
    <?php endif?>
<?php endif; /* if ($this->getDisplayMinimalPrice() && $_minimalPrice && $_minimalPrice < $_finalPrice): */ ?>
</div>
<?php else: /* if (!$_product->isGrouped()): */ ?>
<?php
$_exclTax = $_taxHelper->getPrice($_product, $_minimalPriceValue);
$_inclTax = $_taxHelper->getPrice($_product, $_minimalPriceValue, true);
?>
<?php if ($this->getDisplayMinimalPrice() && $_minimalPriceValue): ?>
    <div class="price-box">
        <p class="minimal-price">
            <span class="price-label"><?php echo $this->__('Starting at:') ?></span>
            <?php if ($_taxHelper->displayBothPrices()): ?>
                <span class="price-excluding-tax">
                    <span class="label"><?php echo $this->helper('tax')->__('Excl. Tax:') ?></span>
                    <span class="price" id="price-excluding-tax-<?php echo $_id ?><?php echo $this->getIdSuffix() ?>">
                        <?php echo $_coreHelper->currency($_exclTax, true, false) ?>
                    </span>
                </span>
                <span class="price-including-tax">
                    <span class="label"><?php echo $this->helper('tax')->__('Incl. Tax:') ?></span>
                    <span class="price" id="price-including-tax-<?php echo $_id ?><?php echo $this->getIdSuffix() ?>">
                        <?php echo $_coreHelper->currency($_inclTax, true, false) ?>
                    </span>
                </span>
            <?php else: ?>
                <?php
                $_showPrice = $_inclTax;
                if (!$_taxHelper->displayPriceIncludingTax()) {
                    $_showPrice = $_exclTax;
                }
                ?>
            <span class="price" id="product-minimal-price-<?php echo $_id ?><?php echo $this->getIdSuffix() ?>">
                <?php echo $_coreHelper->currency($_showPrice, true, false) ?>
            </span>
            <?php endif; ?>
        </p>
    </div>

Answer 1

I would add the sample product as a upsell or related product to show it on the grouped product price.

Then use a shopping cart price rule to set the price to 0 for certain groups. The rule should look something like this

Answer 2

The minimal price is calculated by the indexer. In this process it's not that easy to get the actual product and thus it's SKU. We do however have access to the tax class for the product.

So thinking out of the box, we can create a special Tax class for samples. Then with a little modification in the indexer, we can exclude that tax class from updating the lowest price in the minimal price calculation loop:

diff --git a/app/code/core/Mage/CatalogIndex/Model/Resource/Data/Grouped.php b/app/code/core/Mage/CatalogIndex/Model/Resource/Data/Grouped.php
index 98570ef..15f4330 100644
--- a/app/code/core/Mage/CatalogIndex/Model/Resource/Data/Grouped.php
+++ b/app/code/core/Mage/CatalogIndex/Model/Resource/Data/Grouped.php
@@ -42,6 +42,8 @@ class Mage_CatalogIndex_Model_Resource_Data_Grouped extends Mage_CatalogIndex_Mo
      * @param int $store
      * @return array
      */
+    const SAMPLE_TAX_CLASS_ID = 7;
+
     public function getMinimalPrice($products, $priceAttributes, $store)
     {
         $result = array();
@@ -68,9 +70,13 @@ class Mage_CatalogIndex_Model_Resource_Data_Grouped extends Mage_CatalogIndex_Mo
                 $retreiver = Mage::getSingleton('catalogindex/retreiver')->getRetreiver($type);
                 foreach ($typeIds as $id) {
                     $finalPrice = $retreiver->getFinalPrice($id, $store, $group);
-                    if ((null === $resultMinimal) || ($finalPrice < $resultMinimal)) {
-                        $resultMinimal    = $finalPrice;
+                    if ( (null === $resultMinimal) || ($finalPrice < $resultMinimal)) {
                         $resultTaxClassId = $retreiver->getTaxClassId($id, $store);
+                        if( $resultTaxClassId != self::SAMPLE_TAX_CLASS_ID ) {
+                            $resultMinimal    = $finalPrice;
+                        }
+                        else
+                            unset($resultTaxClassId);
                     }

                     $tiers = $retreiver->getTierPrices($id, $store);

Of course, you should do this properly in an extension and the hard-coded constant there, should probably be a configuration setting.