Media and ink
Media is the vinyl or banner material you print on. Price it per square foot from the roll cost, then add your waste factor for test prints, trim and offcuts. A 10 to 15 percent waste factor is common on banner work, but set the one that matches your shop.
Ink is easier to miss. Many shops use a flat ink cost per square foot by print mode. A heavy color design in a high quality mode uses more ink than a simple two color layout. SignEstimator lets you store ink cost per square foot per mode, so the estimate matches the file.