From the original screenshot in the post, it looks like it debuted at $0.99, I wonder if there's a way to look up App Store price history
I looked the app on Appannie (non paid account) and the pricing history is quite interesting:
26 Mar 2017 - 0.99 to Free
29 Mar 2017 - Free to 0.99
19 Jul 2017 - 0.99 to 1.99
20 Jul 2017 - 1.99 to Free
02 Aug 2017 - Free to 0.99
04 Feb 2018 - 0.99 to Free
10 Feb 2018 - Free to 0.99
03 Mar 2018 - 0.99 to Free
27 Mar 2018 - Free to 0.99
04 Dec 2018 - 0.99 to Free
03 May 2019 - Free to 0.99
05 Sep 2019 - 0.99 to Free
From the above details, it was a paid app for most of it's time. I wonder why the developer played with the pricing as much though?
I would often change the price to 1. See if I could squeeze a few more dollars out of the work and 2. Generate more downloads.
A fun "trick" for getting more downloads is to temporarily make a paid app free, as many, many people follow "Apps Gone Free" type of bots or directories and if your app has any substantial numbers behind it more people tend to notice when it switches to free.