You are considered a “Sailfish customer” if you have had a Sailfish device and signed in to your Jolla account previously, and bought a Sailfish X licence previously. == SORRY, my mistake, a communication problem ==
Now, sign in to https://shop.jolla.com/ with your Jolla account credentials (top right area). Click BUY under Xperia 10 II. You should see the price 29.90 € there.