Our trip to the South African veldt started poorly since we left our insulin at home when leaving for the airport. A year ago, it would have stressed us out, but, by now, we have purchased insulin for cheap and without prescription in so many countries that we did not worry.
Landing in Cape Town, I called a pharmacy to verify they would sell us some. We arrive there at 10:55pm, right before closing time. We were able to buy 2 boxes of 5 Novolog (Novorapid here) cartridges for US$42 per box, and two pens of Lantus (backup, in case we have a pump problem) for US$15 per pen (based on the Novolog prices, it is about 30% cheaper to buy a whole box btw, so that would put the Lantus box of 5 pens around US$53, a pretty good deal).
We did not need a local prescription, or, indeed, a US prescription either.
This must be the sixth or the seventh country where we bought insulin without prescription and quite cheaply 
I am a few days behind on telling the tale. But I will write up the whole trip. We are getting ready to enter the veldt soon!!!