http://www.freecodecamp.com/p1xt 's solution for Bonfire: Exact Change

bonfire-exact-change.js

// Bonfire: Exact Change
// Author: @p1xt
// Challenge: http://www.freecodecamp.com/challenges/bonfire-exact-change
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function drawer(price, cash, cid) {
  var change = [];
  var types = ['PENNY', 
               'NICKEL', 
               'DIME', 
               'QUARTER', 
               'ONE', 
               'FIVE', 
               'TEN', 
               'TWENTY', 
               'ONE HUNDRED'],
      values = {
                PENNY: 1,
                NICKEL: 5,
                DIME: 10,
                QUARTER: 25,
                ONE: 100,
                FIVE: 500,
                TEN: 1000,
                TWENTY: 2000,
                'ONE HUNDRED': 10000
              },
      cashback = Math.round((cash - price) * 100),
      type = types.length - 1,
      changeAmount = 0,
      cashLeft = 0,
      remainingchange, value, availableChange, drawnChange;
  
  // while we still have cash in drawer
  // and haven't given the full cashback due
  // loop through the currency from largest denomination to smallest
  while (type !== -1 && changeAmount !== cashback) {
    remainingChange = cashback - changeAmount;
    value = values[types[type]];
    availableChange = Math.round(cid[type][1] * 100);
    
    // we used up all this denomination, drop to smaller
    if (value > remainingChange || availableChange === 0) {
      type--;
      cashLeft += availableChange;
      
    // finished before denomination gone, push amount
    } else {
      drawnChange = Math.min(availableChange, remainingChange - remainingChange % value);
      changeAmount += drawnChange;
      cid[type][1] -= drawnChange / 100;
      change.push([types[type], drawnChange / 100]);
    }
  }
  
  
  if (changeAmount !== cashback) {
    return 'Insufficient Funds';
  } else if (cashLeft === 0) {
    return 'Closed';
  } else {
    return change;    
  }
}

drawer(3.26, 100.00, [['PENNY', 1.01], ['NICKEL', 2.05], ['DIME', 3.10], ['QUARTER', 4.25], ['ONE', 90.00], ['FIVE', 55.00], ['TEN', 20.00], ['TWENTY', 60.00], ['ONE HUNDRED', 100.00]]);

// Example cash-in-drawer array:
// [["PENNY", 1.01],
// ["NICKEL", 2.05],
// ["DIME", 3.10],
// ["QUARTER", 4.25],
// ["ONE", 90.00],
// ["FIVE", 55.00],
// ["TEN", 20.00],
// ["TWENTY", 60.00],
// ["ONE HUNDRED", 100.00]]

drawer(19.50, 20.00, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);