I've used MoneyWorks for several years to do my accounts for part time self-employed income. A basic understanding of accounting principles is helpful. I'm not an accountant but understand enough about it to be able to do my end of year tax returns, and I also use it for my GST returns.
I originally used CashWorks (now "MoneyWorks Cashbook"

and recently upgraded to MoneyWorks Express to get some extra features.
Cashbook is fine if all you need is to track income and expenditure, including GST. I upgraded to Express so that I could also handle debtors and creditors. The Gold edition adds several more features which I don't need.