The latest promo code sale on Spirit Airlines allows you to take up to 75% off the base fare for travel this summer and fall. Fares start at just $49 roundtrip.
Just enter promo code 75PCTwhen booking on Spirit.com to apply a 75% discount to the base fare for roundtrip travel on Tuesdays, Wednesdays, and Saturdays, from August 28 through December 12. Avoid blackout dates on September 1, October 6, and November 15-27.
The discount will only apply to the base fare and not to taxes nor Spirit's booking fees so don't expect to see that large of a price drop on certain routes. There is also a list of excluded markets for this sale. However, I found that if you start your search directly from the sale page, all routes are being discounted, even if they are listed as excluded.
There are many more routes available as well. Domestic routes will work in reverse. Lowest fares may not be available for the entire travel period. You'll have to decline any extras to get the lowest price.
Spirit's Bare Fares only include one small personal item (small backpack, large purse, briefcase, etc.) that will fit underneath your seat. Checked baggage starts at $30 each way. Larger carry-on bag fees start at $35 each way.