How does my tax work if I am the sole proprietor and sales person of my estate agency?

Is you agency a registered entity or your own business in your name?

I am just registered with the EAAB, nowhere else.

Then you would be taxed as normal individual as per the tax tables announced in the 2015 Budget. You would need to register as a provisional taxpayer and file three returns a year.

All expenses directly related to earning your income can be claimed as deduction against the income earned.