The income amount is static. The purchase amount is variable (therefore the 50% discount is able to scale)
For that reason, I'd go with the discount.
The only reason the income amount choice would be attractive if is if there was a compounding component that allowed the amount to scale.
You could even generate a huge amount of income using the first option.
For instance, if I purchase a house that is appraised at 500,000 for 250,000, I instantly have 250,000 dollars worth of equity. I can just sell, collect the 250k equity, and apply it to a more expensive home for which I will then immediately earn equity. You would only need to do this a few times to become a billionaire.
Here's the path to 1 billion dollars if you increase the home purchase price in accordance to the equity earned on last sale:
This is essentially what flippers do, except we don't have to do any extra work because the capital gain comes from the 50% discount of the purchase (which is unique to us and does not affect the appraised value of the home). This removes the inherent risk involved in property flipping and turns it into an infinite money glitch.
You could essentially do this with
any item you buy and resell. As long as the market value is higher than what you paid, you'll earn a profit. It's just that bigger ticket items are more efficient to flip.