Okay, I'll jump in to the fray.
If spend $12.00 for a roll of Acros II 120 format and out of ten images I get one that I print, hang on my wall that I'm proud of, the cost to me is more than justified.
If I spend $24.00 for two rolls of 35 mm for 72 images ( 0.33 cents a piece) of my cat, my dog, my wife, my mother, the post man, my Christmas Tree, my favorite bottle of Tequila, images that I will have forever, than the cost is more than justified.
All predicated that Acros is an emulsion that I enjoy. At $12 for an image from 120 or at 0.33 cents an image from 35mm Acros seems very affordable. Can I cut my costs in half with another film choice, certainly.
But if the quality and aesthetic of Acros is appealing to me, cost is not a large consideration at $12.00 a roll, the look of my prints is.
On average Ilford 120 film is half the cost of Acros currently.
On average Kodak is $8 a roll for black and white.