Lot sizing is 10 ounces of gold per lot, so 1 lot = 0.10 USD/pip
For example, the XAUUSD spread is 0.55 at FOREX.com, so you are 5.50 USD in the hole upon execution of a buy order. Hope this helps.
They also have fractional silver which I have found useful due to their more manageable position...
One lot at FOREX.com is equal to 10 ounces, so this could be what you are looking for. You would need to trade 10 lots with them in order to equal one COMEX contract. Of course, they are a bucket shop, but that is a different issue.