Here’s a major tip for those that need a Aussie Electronic Travel Authority (ETA). While most would go to their official website to apply for one (AUD$20), you can actually save a lot by applying through a third party.
I came across this lady Miss Kang on hardwarezone http://forums.hardwarezone.com.sg/75322824-post222.html , and she specializes in making legit Aussie ETA for just SGD$7 per person. Originally I thought it was some kind of scam until I read all the posts on the forum thread and realized that even my colleague would had been to Australia had done the same.
So I contacted her, and within 30 minutes it was done, for a fraction of the price.
Do remember not to make any mistakes in the information you provide her especially the passport details! I made a mistake of renewing my passport AFTER she applied for the ETA, so I had to redo it again. Still, it was much cheaper had I applied directly through the Australian website. Not sure why, but it works!