I understand exactly what you are getting at. I will say this. With Kodak Flexicolor C-41 chemistry biggest cost is Bleach and bleach starter. And yes the capacity of the bleach replenished is enormous . Having said this the fixer is super cheap (it's regular rapid fix only cheaper ) the developer is cheap and developer starter is cheap. Minilabs use 3 stabilizer baths, at home you wash, skip the stabilizer and use a final rinse, acts as a biocide and wetting agent. Mix with pure water lasts a long time .
I bought everything from Unique photo in New Jersey for just a little over a hundred bucks plus shipping. All I buy now is fresh developer , developer goes bad the bleach is eternal .
E6 is a interesting twist ,the Fuji "kit" just doesn't include starters. It's the same stuff. Freestyle gets 200 bucks for 5 liters of Fuji. You can buy individual components of Fuji but only in sizable quantities.