No need for a VPN, simply apply two codes from previous deals and change the card country.
Go to https://plex.tv/subscription and purchase a monthly subscription for free by using the code "AD-ONEMONTH" from https://www.ozbargain.com.au/node/649435
Go to https://plex.tv/subscription, and cancel the subscription.
Go to https://plex.tv/subscription, upgrade subscription; Enter the code "LIFETIMEOFCOMFORT" from https://www.ozbargain.com.au/node/665533
Select Turkey from the country, don't worry about the postcode, Aussie postcode works fine;
Click next and it will redirect you to the payment confirmation page.On the confirmation page, double-check the amount to pay is ₺617,24 TRY, click next to pay.
Just paid with my Macquaire debit card, ₺617.24 TRY charged for $69.66 AUD
Update
For those having Selected country does not match Credit Card country errors, try this alternative procedure by cnwhite82
Go to https://plex.tv/subscription and purchase a monthly subscription for free by using a free month code "AD-ONEMONTH or HDHR01MONTH or TECHWITHBRETT30" - Make sure you put in your CC details with the country code of turkey.
DON'T CANCEL YOUR SUBSCRIPTION
Go to https://plex.tv/subscription, select upgrade subscription; Enter the code "LIFETIMEOFCOMFORT" and use the same credit card as step 1.
Update:
If you are still getting a wrong country error after tried the above step, you can also try this method mentioned by gamerkonks https://www.ozbargain.com.au/comment/11398973/redir
If you are getting a "Code not valid" error, please make sure you are NOT using a VPN and try to repeat the steps in browser's incognito mode
Got it to work following method described by cnwhite82 below. Had to subscribe for a free month using one of the other codes (setting Turkey as my country) and then upgrade using LIFETIMEOFCOMFORT.