Read this part. It is the whole game.
You earn when
- your tower is flipped within the first day: +15% on what you paid;
- flips happen anywhere in the city while you own a tower: you get your weighted slice of every one;
- you are the last buyer when the Vault timer runs out: you get half the Vault.
You lose when
- you buy at a high price and nobody takes the tower for days. The price decays, and when someone finally buys it you get back less than you paid. Owner income offsets part of that, not all of it.
One player's profit is another player's money. Whoever buys at the peak and doesn't find a buyer in time loses. There is no yield from outside the game and no guaranteed return. Only play with what you can afford to lose.