I am currently charging a one time price for my app https://www.ghostnoteapp.com it's doing pretty well but it's also hard work. I am currently working on a subscription version of my product mostly used for team annotation of websites, something a lot of people have been asking me about. And I really want to move towards recurring revenue as there is much more to work with.
The best trick I can give you is start with a really low price then slowly raise it until downloads slow down but your revenue is intact from your start price.
I don't believe you need to ever introduce ads unless your product provides no real value.
Honestly I believe it needs to be priced less, if possible via use of coupons. I believe ghostnoteapp needs ubiquity and integrations so people buy it to add it into their workflow, as opposed making it the workflow.
Why would it need to be priced less at this point? Based on my experiences, he'll most definitely will be making less money. I don't see it. If anything, he should test a higher price point.
Simple, to attract more people for now. It needs to be ubiquitous imho, and deeply integrated into people's workflow so that when he jacks prices up people have to pay it or break their workflow. (which creates an incentive to actually pay more, as a customer)
The best trick I can give you is start with a really low price then slowly raise it until downloads slow down but your revenue is intact from your start price.
I don't believe you need to ever introduce ads unless your product provides no real value.