Assuming you want to maximize income (and in turn, profit), this becomes a math problem based on data. Income = Price * Conversion Rate. So assuming a constant number of people coming in to your funnel (which should be the case since it is ~independent of price), you can keep increasing price (which likely decrease conversion rate, but not always) until Income goes down. To start, you don't know conversion rate, so set price very low (0 is a good start for a few reasons), and every N sales, increase it by 20% until income stops going up.
Yep - obviously corner cases are left up to the reader! The other way to think about this is to work backwards from your guess of a final price. So that would give you the size of each step. Likewise 20% is a pretty random number and can also be tuned. The key insight is the data and math should drive the decision.
