Some rules to follow when purchasing e-liquid that I have come across.
1. If it's not just a Vape Shop (meaning they sell phones, electronics, clothes, food etc) then their juices are fake.
2. Any fleamarkets, corner shops, china-malls, wholesale places sell Fake juices.
3. The price will give it away, as they usually sell 60ml or 100ml for 80-120 Rand. (But some places are getting smart about this and increasing prices to mimic actual prices)
4. The nicotine content, 99.99% of fake juices are marked as 3mg, usually if you purchase e-juice at a proper Vape Shop you will have a choice between different nicotine content eg. 3 6 or 0 mg.
5. The display of the juices. They will usually just put 100 or so juices on a table where you can't see the labels so you have to pick them up individually and see what they have. There is no order at all.
6. If the person who is selling the juices has no idea what they are talking about, or don't even vape themselves, then they are usually selling fake products to make a quick buck.
7. The taste of the juice, (if you ever buy fake juice by accident) you will have a weird taste in your mouth, the flavour will actually be off putting and there will usually be no nicotine even though it states 3mg.
Best advice is to find a Vape Shop (that only sell vape gear and liquids) in your area that either make their own E-liquids, or sell local juices where you can pick the nicotine strength. It will definitely be more expensive but the taste and pleasure it will give you is definitely worth the extra money. And also you never know what you are actually vaping with the fake juices.