Pete, it's concentrate to make 25 gals. I don't know if they still offer it.
I used to use a 5 gal kit- http://www.adorama.com/KKFCDR5G.html
The box is maybe 10x5x7, really small. You can mix less than full package amounts as well, I'll email you a pdf that is a compilation of all the C41 documents from Kodak in one pdf file.
You can develop a lot of film with 5 gals of developer, unreplenished one shot.
The total cost is very low, low enough that even mixing up a liter or two here and there I still beat the cost of the least expensive minilab pricing around ($2/roll). Not to mention being able to process 120/220, 4x5 and 8x10 negatives at 11:00 at night, should inspiration strike me.
Even before I inherited a nearly lifetime supply of C41 chemistry (sans bleach, damnit...), it still cost me somewhere around $.50 a roll to develop, now the only cost I have is bleach, for the foreseeable future.
Bleach is the only gotcha, shipping surcharges can easily exceed the cost of the product, if you can find a minilab supplier locally, they will have all the chemistry for far cheaper than mail order, even if you figure in throwing half of it away. It may take a bit to find the person there that has the tech knowledge and can help you decide on which chemistry will work best, but in the end it's well worth it.
While I use Kodak chemistry, Fuji-Hunt, Trebla and Champion are all good as well. Just avoid blix, it's one shot, not very effective and expensive in comparison. I've been using the same 2 gals of bleach now for over 4 years, with no leuco cyan staining, which appears when the bleaching is not being completed, and the fixer at around
so Kodak p/n rundown, all prices from Unique Photo Supply (Diversified and Minilab.com's pricing is fairly consistent)
dev/replenisher 1919042 makes 5 gals around $30
bleach 8824690 ready to use around $27/gal *need to order in multiples of 2
fixer 1597392 makes 25 gals cost around $39
final rinse/stabilizer 1925254 makes 5 liters, around $2.75 *need to order in multiples of 12
(there are other options, though the price is triple, so if you anticipate buying 4, might as well get the case of 12)
Also, a final note, the C41 fixer is also a very good b&w fixer, mix 1:3 for film, 1:9 for paper. I keep mine as a concentrate, as for C41 processing you mix 1:4 (the 25 gal cube is really 5 gal cubetainer). so $40 for 5 gallons of concentrate that will make 15 gallons of film fixer, 50 gallons of paper fixer, or 25 gallons of C41 fixer is about the least expensive way to do b&w, cheaper than mixer thiosulphate from bulk.
If you want to try some real fun, film acceleration is where one develops E6 film first in D76 or another b&w developer, then in C41 chemistry, think of it as cross processing on steroids. Limited info here (http://jpgmag.com/stories/1228
). Other effects include bleach bypass, giving an image much more grain and muted colors, partial bleach bypass, and of course cross processing E6 films.
(edit, just found this link, go to 22.07... http://people.rit.edu/andpph/pf-faq/faq-22.html