I've done this, it's a bit hard to explain because we've got a custom theme, but below is the php code and template code to get the "from" thing working. Quite a bit of code because it has to check if each attribute affects the price. In category.php this is what the code looked like "before":
if ($category->id != 1)
{
$nbProducts = $category->getProducts(NULL, NULL, NULL, $orderBy, $orderWay, true);
include(dirname(__FILE__).'/pagination.php');
$smarty->assign('nb_products', $nbProducts);
$cat_products = $category->getProducts(intval($cookie->id_lang), intval($p), intval($n), $orderBy, $orderWay);
}
and this is what it looks like "now":
if ($category->id != 1)
{
$nbProducts = $category->getProducts(NULL, NULL, NULL, $orderBy, $orderWay, true);
include(dirname(__FILE__).'/pagination.php');
$smarty->assign('nb_products', $nbProducts);
$cat_products = $category->getProducts(intval($cookie->id_lang), intval($p), intval($n), $orderBy, $orderWay);
foreach($cat_products as &$cat_product){
$cat_product['all_prices'] = array();
$product = new Product($cat_product['id_product'], true, intval($cookie->id_lang));
$cat_product['all_prices'][] = floatval($cat_product['price']);
$attributesGroups = $product->getAttributesGroups(intval($cookie->id_lang));
if (Db::getInstance()->numRows())
{
$combinationImages = $product->getCombinationImages(intval($cookie->id_lang));
foreach ($attributesGroups AS $k => $row){
$cat_product['all_prices'][] = floatval($cat_product['price']) + floatval($row['price']);
}
}
$diff_prices = array_unique($cat_product['all_prices']);
array_multisort($diff_prices);
$cat_product['from_price'] = (count($diff_prices)>1) ? array_shift($diff_prices) : false;
}
}
Then in themes/your_theme/product-list.tpl this is what it might have looked like before:
{convertPrice price=$product.price}
and this is what i changed it to.
{if $product.from_price}from {convertPrice price=$product.from_price}{else}{convertPrice price=$product.price}{/if}
Examples: http://bastbodyjewellery.com.au/7-eyebrow-jewellery http://bastapparel.com.au/18-punk-accessories