A copy of the receipt you were given for payment when applying to write the test.
Your ID book.
Between R37 and R126 - depending in which province you are in - for the licence issuing fee if you pass your test. The Government Services site used to provide a breakdown of costs by province, but they no longer supply one. Your best option for determining the cost of your licencing fee is to contact your local driving licence testing cetre. Another option is to contact a local driving school or instructor who deals with your local driving licence testing centre - they will generally be aware of what the current costs are. They are subject to change without notice though, so you may always want to bring a little bit of extra money with you just in case.
Bring a spare pen and pencil with you, just in case!
Note: If you are late, or if you have not brought the above documentation, you will not be able to write the test AND you will forfeit any monies paid already! So get there early!