Https://www.steadyhealth.com/topics/what-is-the-cheapest-day-to-book-flights-on-spirithttps://www.steadyhealth.com/topics/what-is-the-cheapest-day-to-book-flights-on-spirit https://www.steadyhealth.com/topics/what-is-the-cheapest-day-to-book-flights-on-spirit