import greenfoot.*;

public class Money extends Actor
{
    private int holdX, holdY;
    long markTime = 0;
    int value;

    public void act()
    {
        if (markTime == 0 && Greenfoot.mouseClicked(this))
        {
            holdX = getX();
            holdY = getY();
            if (value < 250) setLocation(517, 314); else setLocation (664, 367);
            markTime = System.currentTimeMillis();
        }

        if (markTime != 0 && System.currentTimeMillis() - markTime > 1000)
        {
            markTime = 0;
            credit();
            setLocation(holdX, holdY);
        }
    }

    private void credit()
    {
        ((Screen) getWorld().getObjects(Screen.class).get(0)).addCredit(value);
    }
}

import greenfoot.*;

public class FiftyPence extends Money
{
    public FiftyPence()
    {
        value = 50;
    }
}