Note this is an eBay exclusive deal similar to https://www.ozbargain.com.au/node/238586 but with less data (5GB instead of 7GB) but certainly better than https://www.ozbargain.com.au/node/247250 as you receive full services instead of online only.
You cannot access the page directly from Telstra.
You may use this search to get some mobile phone listings:
http://www.ebay.com.au/sch/Mobile-Phones-/9355/i.html?_dcat=…
Looking for any mobile phone listing on eBay and find the link below "Paypal" part as per screenshot:
http://s32.postimg.org/oc7m8zn8l/shot.png
It should redirect you to below page:
http://s32.postimg.org/5m2rpro85/telstrapage.png
This deal should be better than: https://www.ozbargain.com.au/node/247250 as this one has full support.
Some fine prints at the bottom of the page:
Go Mobile BYO Plan: Some usage is excluded, such as calls/text/MMS to premium numbers (e.g. 19xx numbers), 1234, 12455, 12456 and satellite numbers, content charges and use overseas. Unused allowances expire monthly.
BYO Handset: You need to BYO a Telstra Mobile Network compatible handset to take up this plan. Check that your handset supports 3G-850MHz and both 4G 1800MHz and 4G 700MHz to ensure you get the best possible experience on the Telstra Mobile Network. See telstra.com/device for more information.
Extra Data: Extra Data is for use in Australia with eligible plans, is shared between eligible data sharing services on your account and expires at the end of that billing month.
You're better off with an Aldi XL plan for $35 per month. There's no contract, comes with unlimited calls, uses the same network and has 5gb allowance too. https://aldimobile.com.au/plans/xlvaluepack