In Tint Wiz inventory, every film type has an overview page you can use to review basic information for that film type, see the list of rolls you have and, set your retail price.
Below is an example film type overview page:
You can see a summarized list of rolls of this film type at the left and the film type information at the top on web version.
You can tap "Settings" to change your Price per sqft for this film type to be used in calculating fixed price on proposals.