The GST/HST credit is a non-taxable quarterly payment that helps individuals and families with low and modest incomes offset all or part of the goods and services tax/harmonized sales tax that they pay. For self-employed and your total revenue from the sale of taxable goods and services is over $30,000 ($50,000 for public service bodies) in a calendar quarter you must register for a GST/HST number. For you to file your business expenses you may be qualified for a refund from the government of Canada.