The ability to save forms as a pdf is a paid feature.
Is it possible to pay now? NO.
You retire FormsCentral and don't let to download forms. WTF?
You mention "forms" but, if I recall correctly, only users with paid accounts were able to create more than one form. If you have more than one form but cannot save the forms as PDF, it is likely that one of the following is the case:
-- You used to have a paid account at one point in time but have since canceled your subscription. If this is the case, please let us know.
-- You had a free account but others with paid accounts have shared forms with you. If this is the case, please contact the form author, who would be able to save the form and send you a copy.
If you have only one form which was created using a free account, you would not be able to save it as PDF. However, you could migrate the form to another form solution. Some of the services listed on the retirement FAQ (FormsCentral: Retirement FAQ) provide migration tools specifically designed for FormsCentral forms.
Regardless of which of these cases apply to you, please keep in mind that FormsCentral is going away on 07/28, so make sure to save or migrate your form by 07/27.