What am I?

I am part of your life.

Some people have lots of me,

While some people have less.

I am a major part of politics

And the cause of economical distress.

I insire greed,

But greed causes you to want me.

I cannot be bought,

But you can buy things with me.

I am of value when you have me,

But I mean nothing without.

I am your friend,

As well as your enemy.

I am your need, 

But you mean nothing to me.

I am as green as the earth,

But you want me in your purse.

I am universal,

Though my name may differ.

I cause your actions,

And I don't have to say a word.

What am I?

I am the money that you seek.