Enter in name ....need a little bit of help!

Hey guys i'm working on a following project that gives a person how much money there car is going to be with sales tax. here is my code

import java.util.Scanner;
import java.text.DecimalFormat;

public class tad
{
public static void main(String[] args)
{
final double INTEREST_RATE = 0.075;
DecimalFormat df = new DecimalFormat("#,000.00");

Scanner s = new Scanner(System.in); // create a Scanner object
String input; // read in user input as a string
double carPrice;
double carTax;
double carTotal;
double personName;

System.out.print("Please enter your first name ");
input = s.nextLine();
personName = Double.parseDouble(input);

System.out.print("Enter the price of the car: "); // user prompt
input = s.nextLine(); // read input as a string
carPrice = Double.parseDouble(input);

carTax =(carPrice*INTEREST_RATE);
carTotal=(carPrice + carTax);
System.out.println ("The Sales tax on your purchase is $" + df.format (carTax));
System.out.println ("making the total $" + df.format (carTotal));

}
} this is what the programs looks like running

Please enter your first name 99 (i put 99 because i get an error when i type in a name)
Enter the price of the car: 12345.67
The Sales tax on your purchase is $925.93
making the total $13,271.60

it needs to look like this....
Please enter your first name Adam
Enter the price of the car: 12345.67
Adam,
The Sales tax on your purchase is $925.93
making the total $13,271.60.

thanks alot for your help fellas!