[dagw]

A $700 juicer that you could use with your own ingredients would not be a problem (In fact I'm sure there are plenty of $700+ juicers on the market already[0]). A $700 juicer that can only use ingredients from one company (and only if they let you) and that gives you zero control over the content of the juice is a just dumb. If I was the sort of person that considered $700 reasonable for a juicer, I would absolutely also be the sort of person who would want to experiment with different juice ingredients and ratios.

[0]I know several people who own Vitamixes and only use them for juice/smoothies, and they cost more than $700.