The only thing expensive about South Africa is getting there from Europe. Once you are there food, drink, accommodation and transport are all very good value for money. You can really afford to push the boat out… we had fillet steaks on a very regular basis.
The weather is good and if you experience rain or storms, these are quite a spectacle in themselves. Do the game parks and drag yourself out of bed in the mornings for guided tours. The guides know when and where to find the animals and can identify them too.
Have a splash in the Indian Ocean and then in the Atlantic.