Working on a free visa as a freelancer (Muscat)

I am still in the process of figuring out if Oman is the place where to go, as I am able to work from anywhere in the world just over the internet. Oman would be the best place in the world where I could save most of my earnings (which are relatively low for Germany and too low to survive here on long term), and at the same time be in a very attractive and safe country.

My question is, if I find a sponsor for giving me a so-called free visa to work as a freelancer there, will my wife also be able to come there and receive a visa in order to be able to live there, or how would be the proceedings for this?

And does anyone have an idea how much a sponsor normally takes per year for providing the free visa?