Get minimal price

gistfile1.aw

<?php
/**
 * Grouped price display
 */
function mamaduka_wc_grouped_price_html( $price, $product ) {
	$all_prices = array();

	foreach ( $product->get_children() as $child_id ) {
		$all_prices[] = get_post_meta( $child_id, '_price', true );
	}

	if ( ! empty( $all_prices ) ) {
		$min_price = min( $all_prices );
	} else {
		$min_price = '';
	}
	
	$price = '<span class="from">' . _x('Starting at:', 'min_price', 'woocommerce') . ' </span>' . woocommerce_price( $min_price );

	return $price;
}
add_filter( 'woocommerce_grouped_price_html', 'mamaduka_wc_grouped_price_html', 10, 2 );