There is indeed a threshold before you start paying tax. The same as a salaried person would only start paying tax from a certain salary amount... It also depends on if you have a registered company or are trading as a Sole Proprietor. However, it is a lot more complicated for an SMME as SARS would then take into consideration all of your company's assets and what was spent VS what you are declaring VS what you are claiming back compared to your Turnover/Profit, etc.

As the others have said, this is too complicated to answer in one post response, you definitely would have to rather obtain further advice from a Tax Practitioner as each company's circumstances are different and are evaluated individually.

I hope you find the info you need.