For some reason I can never get the BTC one to work with coinbase.

url: http://coinbase.com/api/v1/prices/buy

sample json:
{
  "subtotal": {
    "amount": "577.40",
    "currency": "USD"
  },
  "fees": [
    {
      "coinbase": {
        "amount": "5.77",
        "currency": "USD"
      }
    },
    {
      "bank": {
        "amount": "0.15",
        "currency": "USD"
      }
    }
  ],
  "total": {
    "amount": "583.32",
    "currency": "USD"
  },
  "amount": "583.32",
  "currency": "USD"
}


I try:
json.total.amount
amount

but nothing comes up