The problem properties that cannot be sold ends up there.
Have a look at the Gumtree property section, it is super busy and up to date.
Alternatively, identify specific areas and have a look at property agency websites.
Having bought a place recently in Sea Point, I can say with 100% confidence this is wrong.
For the City Bowl and Atlantic Seaboard, properties will be on Property24 the moment it goes on the market. I know this because I'm subscribed to property viewing emails and I also browse Property24.
That said, I wouldn't buy until I've lived in CT at least 2 years.
Last but not least, renting in City Bowl (eg. Vredehoek, Gardens, Tamboerskloof, Oranjezicht, CBD, Higgovale) or Atlantic Seaboard (eg. Green Point, Sea Point, Fresnaye, Camps Bay) you will generally look at R10k-R15k per month for a 2 bedroom apartment.
The City Bowl can be damp and cold due to the shadow of the mountain (I stayed in Gardens for a year and Tamboerskloof for a year)
Camps bay and Vredehoek is super windy (no seriously, trust me on this, I stayed in Camps Bay for a year, wind was horrible)
Both those areas are good if you work in town. Especially Seapoint and Fresnaye, much less wind, warm, plenty of sun, beautiful location with lots of attractions that you can walk to (eg. promenade, main road has plenty going on, green point park, waterfront, etc.). I ended up buying there after staying there for 2 years of great living. but YMMV.
If you consider town the above should get you started.
You'll want to look here:
http://www.gumtree.co.za/
Last but not least, renting in City Bowl & Atlantic Seaboard is competitive. Anywhere from 5 to 20 individuals can show up for a viewing to rent. So you'll want your forms pre-filled out, 6 months bank statements, proof of employment, etc. with you when going for a viewing.
glhf