I use a version of SignCraft's pricing guide for square footage retail costs of cut vinyl (modified for detail and type of vinyl). I add all the vinyl together to get total square footage.
Example: 2' x 3' 3-color doors (2x) cast vinyl
Black: 12 sq. ft.
Red: 6 sq. ft.
White: 9 sq. ft.
Total: 28 sq. ft. @ $15.65 (2019 blue column) = $438.20
Total retail price (graphics only, does not include design or installation)
By contrast, pricing for same set of stickers using digitally printed 3M 180 IJcv3 with 3M 8158 laminate:
28 sq. ft. @$4 = $112.00, w/ tax $121.80, w/shipping and contour cutting added $151.80, w/40% margin = $253.00
One hour set-up/ordering time: $70
Total retail price (graphics only, does not include design or installation): $323.00
For all but the simplest one-color or two-color jobs, digital printing is likely going to be the least expensive option.