they are just normal units where it was previously booked by others but then their loan get rejected and developer reopen the unit for other to purchase again, not much difference with other units

sometimes when only few units left and they rush to close sell off those unit maybe they will give better discount, most of the time they just trying to give perception that their project is hot selling and tempt you to secure the unit by saying 80% is sold while showing you the sales chart

unless you can get very low entry, there are so many house/room for rent near to city center and you have to compete with others either with better furnish/deals or lower your monthly rental, another strategy is to rent out your unit and expect lower profit but just enough to cover your loan and cost then hope that after 5 years your property appreciate then you sell it