Electronic Travel Authority.
You either do it online and pay the fee, or a travel agency can do it free of charge if they are willing to. In fact years ago United Airlines would do this for you.
Travel industry can handle ETA application free of charge. On Flyertalk travel forum for years there was a guy who owned a travel agency in Singapore, offered to do Australia ETA for free, on the condition that those being helped would "Pay It Forward" by doing some good deeds of their own choosing. We were helped several times. Our "Pay It Forward" were donations to our PBS stations.