I'm assuming (a) your coin is from Mexico and (b) came from circulation, i.e., pocket change.
If that's the case, I'm afraid the answer is Not Much. Mexico's currency was severely weakened by inflation during the 1980s to the point where even small items cost thousands of pesos. During 1992-93 the existing peso was phased out and replaced with a new peso at an exchange rate of 1000 to 1, in effect lopping three zeros off of all prices.
That means a 1000-peso coin from 1989 is worth 1 new peso, which is at current exchange rates is all of roughly 10 U.S. cents.
It is a gold coin named Centenario, worth USD$1,244.
$1000
I hope you know the coin is not gold, just gold colored. Unless it's a proof coin it's only worth a dollar.
The coin is a common bicentennial Eisenhower dollar that MAY have been gold plated or just toned a gold color, the coin is face value.
It likely just looks gold colored, the US Mint has never made a coin one cent coin.
You are likely referring to the large aluminum-bronze coin (no gold content), picturing 17th century Sister Juana de Asbaje on front. In perfect uncirculated condition, this coin would have a value of approximately $5.75 to a collector - and in circulated condition, up to $2.
About $300
It's just a dollar, spend it.
About $1000 for its gold content, regardless of mint mark.
Like the Sacagawea and Presidential dollars in this country, it is not made of gold, it's a gold-colored coin made of base metals. Assuming your coin came from circulation it's a standard issue that is worth only face value, about 95 cents U.S. at current exchange rates.
The P or D denote where the coin was made. P=Philadelphia Pennsylvania, D=Denver Colorado. If by "gold coin" you're referring to the Sacajawea dollar, it's brass, not gold - just golden colored.
$1. Ikes were never issued in gold or gold-colored metal, only in cupronickel for circulation and silver for collector sets. Your coin was almost certainly plated for use in jewelry or something similar.