This sign needs to withstand the elements for months, even years. The customer wants to be able to remove or install the sign at will, and wants to be able to store it in a closet or a car trunk for easy transport. Further, your customer has a deadline for the delivery of the sign, but has very little advertising budget to cover its expense. Because it takes as much time, talent, facility and personnel commitment to create an effective banner sign as it does to create any other quality sign production.
Good banners are also as expensive in material cost as most other producer-supplied sign components.
The only adjustment that can be made when pricing a banner is in the material used and the media to decorate it. The current professional and public perception is that banners constitute a class of quick, easy, cheap signage. This attitude can be changed only by sign companies willing to educate themselves, their clients and their competition - in that order. I agree that banners can be quick. I also agree that banners can be easy.