The ��16 transfer fee is not bad for both of you(but NOT per person!) If you do decide to use a taxi/shuttle make sure it is an official licensed one almost as you would over here in the UK.
DO NO use public transport, especially any minibus taxis. You will see thousands of these on the roads. They are dangerous, mostly unroadworthy, used by the masses and definitely not for tourists. Also do not attempt to use metro trains. You will get robbed.
Do not want to scare you, you will have a lovely time, but stay away from public transport. Hire a car or take a licensed taxi (not mini bus).
Insurance: Travel agents rip you off. Search for travel insurance on the web. You should be able to get insurance for a fraction of that price.
Hope this helps!
(originaly from Cape Town, now living in UK)