The rental prices in Singapore are very high. If I wanted to rent a studio flat close to where I work I would have to pay S$3500+ and it wouldn't be easy to find. To live alone it is very expensive; sharing is a bit better and that's what I opted for.
A lot of Tokyo apartments are small and well designed and the quality of materials is fantastic. They are also very well maintained. Apartments in older buildings still look great. And the prices are reasonable. Varying the size / distance to the centre / condition of the building gives you a wide spectrum. Something should fit your pocket.
In Singapore the options are much more limited. I'd rather take a well designed 20-30m^2 studio than overpay for 50m^2; for me that's a waste of space. I don't need a small and mostly useless condo gym; I'd rather pay for a proper gym membership. Swimming pool might seem nice initially but think about how much you pay for it in rent (whether you use it or not). Unfortunately all condos have "amenities". And that "added value" isn't free.
There's also a crazy "double agent" system in place in Singapore. When you see an ad online it is not uncommon that it has been placed by "agent" that has nothing to do with the landlord. They insert themselves between you and the landlord's agent. So you call them up and it turns out they might not even know on which floor the apartment is on! (happened to me more than once). Because the other agent didn't tell them... And as you might expect both agents expect to be paid. This is usually 1 month per year of lease, even on your re-contract. You're supposed to pay your agent off and the landlord is supposed to pay their agent off.
Another weird thing is that you'll never see the photos of the apartments online. Most of the time the photos are just generic filler. The agents post their own mugshots though (crazy, right?).
Finding a flat in Singapore wasn't a pleasant experience.