If you already have a supported xperia model sailfish does provide a free trial. Otherwise yeah it’s commercial, though it might be worth it if everything works fine. Furiphone is also interesting, hadn’t heard of it before.

SailfishOS supposedly runs Android apps. This is probably what I’ll try once my phone is added to the supported list. There is also AppSupport that should allow Linux phones to run android apps but haven’t looked into it.