What is the total price of all the books ordered by Lucas Wyldbore?
total price refers to Sum(price)
SELECT SUM(T1.price) 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 WHERE T3.first_name = 'Lucas' AND T3.last_name = 'Wyldbore'