There is a processing fee associated with some payment methods. Check the service fees table to see the fees that apply.
If you have a discount coupon, check the section I have a discount coupon, how can I used it to pay for my booking? and you will find detailed instructions on how to use it.
If you have received Volotea Credit and you would like to use it, please see our section How do I use my Volotea Credit on a new reservation? And if you still do not know what it is, find out in What is Volotea Credit?