I made a quick chart of parking price vs days parked for various options, including getting an Uber Taxi or MyCiti bus from Cape Town CBD to the airport.
While MyCiti bus is the cheapest I want a door-to-door service (either my own car or a taxi.) But if you're on a budget then MyCiti is the clear winner (about R50.00 each way.)
- Shaded parking in P3, P4 is cheapest up to 5 days.
- Long Stay parking in P5 is cheapest up to 12 days.
- And then Uber to the airport and back is the best option.
Interestingly, the Katanga Valet parking (which includes a wash, vacuum, polish) is not much more expensive than the Garage parking (in P1, P2.) Having used them before, I'd recommend it - especially if you are late and just want to dump your car and run to the check-in.