Sorry I've just read my last response back and it is hard for me understand!! I was seriously rushed while typing it. To summarize the above:
i) Systema in my experience has been pretty affordable, though someone somewhere is probably making a lot of money out of it.
ii) Other breathing systems I've study through things like Yoga and Aikido teach long deep breathing regardless of whats happening.
iii) In contrast, Systema teaches a different series of breath exercises, depending on whats going on on the outside and on the inside.
"Let your food be your medicine, and your medicine be your food"