Dr Mike runs a medical practice in Victoria. During the first quarter of the 2021 tax year, he receives $5000 in fees from patients (you can disregard Medicare for this question) and $1000 in consulting fees for a pharmaceutical company. He paid $50 for fresh milk and $10 for teabags for the staffroom. He paid $600 to clean his practice rooms, as well as a penalty of $200 for a fine he incurred whilst speeding on the way to the hospital. He paid $500 for his electricity bill and $400 to his friend to fix the drains of the practice (he paid in cash and the friend did not provide a tax invoice).

Determine the net GST for the tax quarter ended 30 August 2020, assuming that a valid tax invoice has been provided unless stated otherwise.