Use a VPN and login from turkey go to Deezer website.
Login using your account as normal
Select the option to buy gift card and select it for one year comes in at 119 Turkish lira which is 20 euro on today's convertion.
Use your card and select email address you want to send code to.
After payment goes through you can exit the VPN and enter the code received to your email onto your account.
Happy days years Deezer for 20 euro
I had to try my card 3 times before it went through.
But I have activated the code and all is working fine.
mod edit seems you can stack the gift cards. Also you can sign up to initial year for just 99 TL and then buy gift cards to stack for further years