Gold coin values can be unpredictible and fluctuate with the rise and fall of the gold market, but historically gold coins and the US Bullion coins have been a good investment. However, there's a couple hedges against the falling and rising gold coin values: One is buying the rarities since their numsimatic value far out paces their gold melt value, two is buying certified mint state gold coins since the higher the grade the more valuable despite the current gold market trends.
These to hedges see very little fluctuation in value and I would rather save and buy just one gold coin that will increase in value, based on it's rarity, than to have ten common gold coins that tend to fluctuate in value at the drop of a dime in Washington.
As a reminder, the coin values in the following pages are just guides, they give you one of many resources to help you determine what your gold coins are worth. It's a reflection of what the coin has sold for, but not what your coin might sell.