I'm trying to figure out what is the least amount I can charge my customers, so that my product does not fall below a threshold that leaves it cashflow negative, requiring us to shutter our services.
Regarding your exact question, since there’s no average number of customers (denominator) or average total expense (numerator), there’s also no use in an average cost-based price. About as close as one can get is to look at the average gross and net (ie, overall) margin of existing SaaS companies. That’s interesting but not a great way to set prices, since prospective customers don’t know or care. They care what your thing is doing for them and how much that benefit (time savings, pleasure, etc) is worth to them.