Kodak 5 L kit. You can usually get it right off of the shelf at Freestyle. I usually get two kits at a time, and mix 2 L at a time and use straight away or within a few days. I mostly use it for 4x5 transparencies in a hand-rotated Jobo Expert Drum. I wait until I have 40 sheets of film to process so that I make full use of the 2 L at 500 mL per batch. I use old crystallized chemicals for cross processing. IME, the developer tends to crystallize with age.
Doing 35mm one shot in Nikkor tanks, with four rolls per liter, it is about $2.50 per roll. Not cheap, even at home. For 120, I usually double roll back to back on 120 reels, or end to end on 220 reels, because if you do not, the cost is $5.00 per roll. To tell you the truth, however, I generally take E-6 roll fim to a lab, as I don't view the cost savings as being that significant for the volume of E-6 roll film I shoot now.
However, with sheet film, it saves a ton of money. Instead of $3 a sheet for 4x5, plus extra money for pushes and pulls (which I almost always do when using E-6), you pay $0.50 per sheet, with free pushes and pulls.