If you pay for your subscription through another country (or via some VPNs), the price is different. I used to have a grandfathered plan from Google Play Music

If you pay for your subscription through another country (or via some VPNs), the price is different. I used to have a grandfathered plan from Google Play Music, and that lapsed (so I lost it) while I was living in Mexico. I got premium for <8usd (it fluctuates with the peso, obviously) and that's locked in as long as I pay in pesos (most American/European/Chinese banks support auto conversion) and don't let it lapse.