Why is Luno saying BTC/ZAR 46 749 while the rest of the sane world says 33 529
Remember that there's no standard/ global Bitcoin price - Bitcoin isn't attached in any way to the USD or any other currency.
There are a number of factors that go into this which we'll touch on a bit below.
The rate quoted on Google and other Bitcoin price trackers will normally link to a much larger Bitcoin exchange, where the price will differ. Each Bitcoin exchange has a price that is solely determined by supply and demand on that particular exchange. So based off that fact, if an exchange sees more people selling the price will likely start to drop. The same goes for more people buying on that exchange, the price will go up. It's a very rudimentary example, but should paint a good picture on how the price is determined.
Another aspect here is arbitrage. This is determined by a few factors, but if arbitrage traders (you can read more about arbitrage here) are able to move money to a certain exchange without any limitations, prices between those two exchanges are most likely quite close. That isn't the case for a market like South Africa, for example, where capital controls are in place and make arbitrage trading difficult and most of the time, not worth while.
This is also a characteristic of a young exchange, as many of our users are new users purchasing bitcoin for the first time. Thus creating the demand on the exchange.
Other, more mature exchanges, do not share this characteristic. To add to this, inexperienced traders often emphasise market movements with herd irrationality due to their lack of knowledge surrounding bitcoin and crypto currency.
If you look at our Malaysian exchange, with more experienced users, you will find that the price is more closely aligned with other global markets.
We can speculate about the causes for this premium but whatever the reason may be for this premium, it is important to note that you are not trading with Luno. We merely provide the platform upon which buyers and sellers interact. The forces of supply and demand determine the price.