I know 25% off has been posted here
But found cheaper way to get the lifetime subscription at Ozbargain. Thanks Stevenx.
No need for a VPN, simply apply two codes from previous deals and change the card country.
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, any postcode should work;
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.
FYI: I haven't tried it as already have lifetime subscription.
Plex brings together all the media that matters to you. Your personal collection will look beautiful alongside stellar streaming content. Enjoy Live TV & DVR, a growing catalog of great web shows, news, and podcasts. It's finally possible to enjoy all the media you love in a single app, on any device, no matter where you are.
Lots more at https://www.plex.tv/
Edit: Looks like people are having mixed outcome with credit card & country. Try below method mentioned by @Iasc
you need to select turkey when subscribing first time using promo for one month(in case you use one you can try those AD-ONEMONTH / HDHR01MONTH / TECHWITHBRETT30) it will pass and store your CC. Then when you upgrade you use lifetime code and use saved CC and don't need to change county it will be Turkey already
Everyone with credit card issues
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.
Worth trying the update method in private browser.