I have made it free at times, but that hasn't seemed to pay off in terms of the additional IAPs. I don't usually do 99ยข, on the theory that anyone willing to pay $1 will be willing to pay $2. Sometimes it is as much as $4.99.
I'm curious to know how often others change the price of their apps, why they change the price (seasonality, experimentation, to get flagged by "sale" aggregator websites that notice price drops), and how it has worked out for them.
https://apps.apple.com/us/app/beeline-reader/id938026867
So my impression has become - either your app is popular or it's not, what you charge (under $5) doesn't seem to make much of a difference as to it being successful or not.