This is unlikely to be reproducible, but I bought a foreclosed condo in Seattle in 2013, did a few weeks’ worth of work (spread out over a year or so) redoing the kitchen and bathroom, and sold it not quite three years later for $120k more than I paid for it.
I also have a couple of super simple apps in the iTunes Store that earn about an iPad a year worth of money.
This seems very reproducible, or at least many people focus on doing this. Donald Trump is probably the most popular example of someone who got rich buying things at low value and fixing it up for a large profit.
It’s not easily reproducible in Seattle any more. The housing market has flattened over the past year or so. Back before 2018, properties would easily go up 20% a year.
I also have a couple of super simple apps in the iTunes Store that earn about an iPad a year worth of money.