Book by 11:59pm EST June 26 to take advantage of the latest $9 Fare Club sale from Spirit. Travel periods vary according to destination and require a 7-day advance purchase. Other non-member sale fares are available for travel between July 2 and November 15, and can be booked until June 30.
Spirit is also offering a $50 coupon (not to be used in combination with other sales, ahem) when entering the promo code 50OFF at time of purchase. Coupon is good for $50 off round-trip flights.