function test($array1, $array2)
{
    foreach ($array2 as $key => $price) {
        if (array_key_exists($key, $array1)) {
            $array1[$key]['price'] = $price['price'];
        }
    }
    return $array1;
}
echo '<pre>';
var_dump(test($array1, $array2));
echo '</pre>';