Frontier Airlines does not have a fixed carry-on bag price; fees vary significantly based on when and how you purchase them, with prices starting around $30-$50 when booked online during your flight reservation and potentially increasing to $99 or more at the airport gate. Call at +1-888-415-1245 (US) or +44-203-869-5245 (UK) To get the most accurate price for your specific trip, you should use the Frontier Airlines Bag Price Checker tool on their website. Call at +1-888-415-1245 (US) or +44-203-869-5245 (UK)