If you purchase by 3/28/2018 and fly by 5/16/2018 you can get airfare as low as $29 one way. In the Houston area it looks like the specials are for Raleigh-Durham and Philadelphia. Markets like Austin have more deals available. https://www.flyfrontier.com/ways-to-save/online-deals/

Southwest Airlines is running specials on certain destinations if you book before 3/29/18. Its valid from April to July and August to October 2018. The fares look to be decent but not the best sale Southwest has had in the past. Its worth a look if you are looking to book airfare to one of the cities included. https://www.southwest.com/html/promotions/click_n_save_sale_180320_offers.html?clk=1325000