experience for every kill

how can i make people give me experience points when i kill them

can i use the same script to make them drop money as well?

In very simple terms, just set up an integer variable on your Player Script like so:

var experience : int = 0;

In your Enemy Script, make a reference to your player object's player script, for example:

var player : PlayerScript;

Then, in the code which handles the "killing" of your enemy, add a line which increments the experience variable on your player, for example:

if (health <= 0) {
    Destroy(gameObject);
    player.experience += 10;
}

For more information about accessing other components and gameobjects, check out these two links:

Accessing Other Objects

Accessing Other Components