What is the value of 2007 dollar gold coin with minting error?

If you are referring to the Presidential dollars that were issued without edge lettering, a fair retail price might be $30 to $40, although I'm sure people are selling them for more on eBay. FWIW, as I assume you know, these coins do not actually contain gold. They're struck in a copper-nickel-manganese alloy that is golden in color, but they only contain a few cents worth of metal.