Making Coin Star Simulator

I have been tasked with creating a coin Star simulator. This accomplishes which accomplishes the following tasks:

Prompts the user to enter coins:

(example inputs): (Note, these can't be like a numerical input followed by a word input, it needs to be one line)

4 quarters
3 dimes
0 pennies

All of which would be allowed inputs.

If an incorrect format is used it should tell the user to use the correct format of number space cointype

After every new input it should give a running total of the current money the system has stored.

this loop should continue until the user enters the phrase "finish"

Then, this system should output the money (minus 9.1% fee) in the largest denominations possible (up to $20)

So if the total came to $ 131.33 (after fee)

It should output:

6 twenties 1 tens 0 fives 1 singles 1 quarter 0 dimes 1 nickle 3 pennies.

and then maybe some cheeky text about how the machine stole your money.

The actual coding for me however is very difficult as I really don't know how to convert the string input from the user into usable numerical and substrings for the calculations.

I have some basic skeleton code worked out, but its only designed to run once.
 
import java.util.Scanner;
 public class CoinStar {
Scanner input = new Scanner(System.in);
public static void main(String[] args) {
/** this first section is supposed to take the string from the user and separate it into two substrings,
* one integer, one word string
*

[Code] ....