Hi
I live in Cape Town and organising your own tour would be much cheaper! There are lovely wine farms 20 minutes from the city center in the Southern Suburbs - Buitenverwachting, High Constantia, Groot Constantia, Constantia Glen, Beau Constantia,etc. The HOHO bus stops at a few of them and most of them will deliver to your home address. Also, don't forget to go up Table Mountain!
Hope this helps.