e3fc0434_anced_seat_selection___Gadling__Premium_Services
[0] Frontier [Earliest available] Lowest economy fares limited to 24 hours before flight, more expensive fares anytime [Charge?] No [Can you pre book an exit row?] Request at check in [Premium Services] 
First few rows with extra legroom free to some frequent flyer members; $15-$25 for others
Once a free perk, many airlines now charge for advanced seat selection - Gadling
Premium Services