I would say the same prize that you will find using the search in this group, or using google and going to the official websites where it's clearly explained. little search and you're done !
You can not travel with them as they are cancelled after 48h. But still they are real in the meantime and at the moment you need to use them as a proof. Don t know why you keep on not understanding. I though many times I know how it works and better than thinking I did use them and checked on airline website. Sorry Ron Think again :) and try it you ll see.