Did not see a place to request carry on or the cost. May have missed when purchasing tickets but only saw an option for a checked bag. Called Frontier and not able to talk with a customer service representative, only online chat. Asked the question for coat and option for a carry on bag. Received the size and weight but no cost which makes me assume it is no charge. When holding for a live chat rep, the chat lost connection twice in over a half hour time frame, still no rep. Will deal with this at the airport, but will no be happy if there is surprises and excessive fees.