If you are facing a problem like no coupon available in your region then follow the following steps.
1) First download
https://moddude.com/nordvpn-mod-apk/ [nord VPN from the given link or you can try the surf shark VPN]
https://vpndudes.com/surfshark-vpn-mod-apk/.
2) Remove SIM
3) Go to setting >Go to apps>Search for Galaxy store app
4) Stop app and clear cache and data.
5) Click on the coupon code then search for the region where the coupon code is available. Copy your code.
6) Start VPN and select your region for which you have coupon codes available.
7) Open the galaxy store and you will your region is changed to the one u have selected the VPN.
8) Apply the coupon code and enjoy.
Please follow the above steps and if u have trouble then follow the process again.
Enjoy and have fun.