There is a general premise in the DIY developer community that our developers are inexpensive. I've been doing a bunch of experimenting lately and noticed that I'm going through some of my chemicals at an alarming rate so decided to take a step back and calculate the real costs of the developers. I'm comparing recipes from the Caffenol blog, PCB/TCB that I've mentioned here, and XTOL for reference.
My final calculation is based on cost per roll in a 250mL tank. My findings (USD) are as follows:
Caffenol-C-M = $1.47/roll
Caffenol-C-H = $1.47/roll
Caffenol-C-L = $0.93/roll
PCB = $0.14/roll
TCB = $0.18/roll
XTOL 1:1 = $0.23/roll
Rodinal (R09) 1+25 = $0.28/roll
For the Caffenol recipes, prices for Sodium Carbonate and Ascorbic Acid are from Photographers' Formulary, price for Coffee is from Amazon (least expensive). For PCB, prices for Borax, Ascorbic Acid, and Phenidone are from Photographers' Formulary. For TCB, prices for Borax and Ascorbic Acid are from Photographers' Formulary, price for Acetaminophen is from Amazon (least expensive). For XTOL and Rodinal/R09, price is from Freestyle Photo.
I have to admit that seeing the actual numbers was an eye-opener for me. Cost isn't everything but it is a factor. Speaking as a frugal photographer, keeping costs less than $0.50/roll is reasonable for an every day developer. Erik's work on re-using Caffenol-C just might be the answer for Caffenol ... we will see.
DISCLAIMER: These are all costs based on one-shot use of Caffenol and ingredients from the retailers mentioned. Sourcing ingredients from different sources may change the posted costs significantly and your actual costs may vary.