I buy from Apmex.com Silver is around $.99-$1.99 over spot depending on if you buy bars or numismatic coins. Gold is between $9.99-$39.95 over spot depending on if you buy a variety of gold coins or bullion. Ofcourse you have to pay for shipping so wait until you have a big purchase to make to make it worth the expense.
I have used both the nucleo exchange and catalog for orders but I find that the catalog is usually cheaper.