I built this in a week, way back when virtually every app in the App Store cost money: https://techcrunch.com/2008/09/04/election-08-for-iphone-off...

Of course, it only had a 3 month shelf life, but I still made about $50k from it. I think the app peaked at #5 or #6 on the top 10 paid apps list and I was making about $1,000 per day from it then.

Fun fact: the data that powered the app was sourced from https://electoral-vote.com, which is operated by Andrew Tanenbaum, the creator of Minix.