They will charge no cancellation figure for the cancellation of tickets within 24 hours of reserving as per Frontier 24 hour cancellation policy. After 24 hours of booking, the frontier will charge cancellation freights as per the departure time frame. The charges could vary from$ 79 to$ 129 as per the time frame between the cancellation and departure time of flight.
Yet if the passenger canceled the ticket before 2 months of departure, the flight won't charge any figure and refund the total cost. Note that the policy is slightly different for award tickets. After the threat period, they don't allow the passengers any refund.