How much is a golden Georgia 1788 worth?

Assuming you mean a gold-colored quarter with an outline of the state of Georgia on the back, I'm afraid it's not gold and it's not from 1788.

Like every one of the State Quarters, it has TWO dates on it. The date 1788 is the year Georgia was admitted to the Union. The coin's actual minting date is at the bottom of the back side.

The reason it's gold-colored is that it's an ordinary copper-nickel quarter that was plated by a private company and sold as a so-called "collectible". However there's almost no market for an individual one of these items. Some niche-type collectors may be interested in a complete set, but a single one is considered to be an altered coin with little or no value to a coin collector.