Write SQL query to solve given problem: Who ordered the book with the cheapest price?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T3.first_name, T3.last_name FROM order_line AS T1 INNER JOIN cust_order AS T2 ON T2.order_id = T1.order_id INNER JOIN customer AS T3 ON T3.customer_id = T2.customer_id ORDER BY T1.price ASC LIMIT 1