Final answer:
Without the specific title or more details, it isn't possible to state the retail price of the most expensive book by Lisa White; research at book retailers or inquiries with publishers would be necessary.
Step-by-step explanation:
To determine the retail price of the most expensive book written by Lisa White, one would need to research the current market prices of her books. Given the information that Lisa White has returned to her career as a well-paid writer, whose books are used in college classrooms, and that one of her books is linked to a three-part series where television proceeds contributed to a significant sum of money, it seems this series could potentially hold the most expensive book.
However, without a specific title or additional context, identifying the exact retail price of her most expensive book is not possible with the provided data. To find the precise retail price, one would typically look at book retail websites, contact publishers, or inquire at bookstores that carry her work.