How can I protect my sound before uploading it?

Hi guys, I’m a new exclusive envato author and I want to upload my first sound.
I have a problem, I live in Italy and if I want to have copyrights on my work I shoul pay more or less 1000 dollars, 500 in taxes + other fees + track fees.
It’s a lot for me, I usually work on recording studios and we avoid this problem making them Associations and not Ltd.
But now I just read that I need something that protect my own job.
I can demostrate in all ways I did my jobs by myself without using third party sounds.
I’m very professional when I work, but unforunally I live in a place where legal Jobs are too expensive for a young guy.
Can somebody tell me me how to defend copyrights of my projects?
Can somebody tell me if it’s obligatory or optional for envato? ?
Thanks anyway.