public function getPriceEstimates($startLat, $startLon, $endLat, $endLon)
    {
        return $this->get(
            '/estimates/price',
            array(
                'start_latitude' => (float) $startLat,
                'start_longitude' => (float) $startLon,
                'end_latitude' => (float) $endLat,
                'end_longitude' => (float) $endLon,
            )
        );
    }