Sam & Christian’s place is where you should stay! Enough space for two and super clean. I arrived a bit late, but Christian waited for me to show me around the place. That was thoughtful. It’s a bit far from the city center, but you can easy catch a Cat bus. Also very close to Subiaco, where is a nice place to walk around.
If I ever come back to Perth, I definitely stay there again. I highly recommend you stay!