"I could give a fuck." means what here?is it common to use nowday?
Drenis:Throw, damn you.

Legatus:Yah!(feign death)

Soldier:What have you done, you stupid shit?!

Drenis:He did what he had to!
Break and go your way!
West if your lives are there.
If not, I could give a fuck.

Soldier:Ohh!
What of the Legatus?

Spartacus:Leave him in the mud.

Question

"I could give a fuck." means what here?is it common to use nowday?
Drenis:Throw, damn you.

Legatus:Yah!(feign death)

Soldier:What have you done, you stupid shit?!

Drenis:He did what he had to!
          Break and go your way!
          West if your lives are there.
          If not, I could give a fuck.

Soldier:Ohh!
           What of the Legatus?

Spartacus:Leave him in the mud.

Answer

"give a f..k" means "care" in a really vulgar way. So in this case it doesn't make any sense. It's common people will say "don't give a f..k" as in "don't care" or "couldn't give a f..k" as in "couldn't care less".

Are you sure it's not "couldn't"? It might be a subtitle error. It's not a normal expression as you wrote it.

Answer

Although the expression "give a fuck" may be commonly used in the United States as Daniel says, it's actually an erroneously used alternative to "couldn't give a fuck", which is the correct expression.

To answer your question Rokr, it's best not to use expressions like these until you have a firm understanding of when they are appropriate.

Answer

Yes, "to give a f*ck" means "to care", but the "couldn't" isn't a mistake. In this case, the implication is "I could, but I don't." This is very common place colloquially. 

What Drenis is saying is: 
"Although I am capable of caring about the situation, I have chosen not to do so."

Answer

Not just united states, it's used in most western countries, like UK, lol, and Australia, NewZealand, Canada, etc....lol.......

I agree with James~~ Listen to his advice~

Answer

in this case it means he can do anything.

cowboy...