NumberFormat

import java.util.Scanner;
import java.text.NumberFormat;
public class Purchase
{
    public static void main(String args[])
    {
        final double tax_rate = 0.06;
        int quantity;
        double subtotal, tax, totalcost, unitPrice;
        Scanner scan = new Scanner(System.in);

        NumberFormat fmt1 = NumberFormat.getCurrencyInstance();
        NumberFormat fmt2 = NumberFormat.getPercentInstance();

        System.out.println("Enter the quantity: ");
        quantity = scan.nextInt();

        System.out.println("Enter the unit price: ");
        unitPrice = scan.nextDouble();

        subtotal = quantity * unitPrice;
        tax = subtotal * tax_rate;
        totalcost = subtotal * tax;

        System.out.println("Subtotal "+ fmt1.format(subtotal));
        System.out.println("Tax: "+ fmt1.format(tax)+ " at"+ fmt2.format(tax_rate));
        System.out.println("Total: "+ fmt1.format(totalcost));
    }
}