We're talking about an app made as a weekend project to solve a problem the developer themselves has. Most normal humans would count their time as being free. I

We're talking about an app made as a weekend project to solve a problem the developer themselves has. Most normal humans would count their time as being free. I pity the person who considers the economic value and tax implications of their leisure time projects. So the calculation is just how many downloads do they need to make up for the $99 developer fee which breaks even at 47 downloads at 30% or 38 at 15%. Definitely not unrealistic.