Pawn shop.
Sacajawea, and the American buffalo
These usually sell in internet auctions for about $1500.
The best thing to do is get a copy of "Red Book" a guide of US coins, it gives information and values for every US coin made, most coin dealers and book stores sell it.
Jimmy Carter's picture has never appeared on a US $1 coin. His picture will appear on a future Presidential dollar if he is no longer living at the time the coin is scheduled to appear; otherwise the coin won't be minted unless Congress passes an exception to the law that prevents living presidents from being depicted on US coins.
If you are talking about the current US $1 presidential series of coins, no. Such coins are struck in brass and lots of them were minted. Other than finding an error coin, those coins will only be worth $1 for the near (and most likely far) future. If you are talking about a coin set not made by the US mint, those sets very often do not appreciate in value past the value of the metals used to strike them.
I am not sure what you have, but any coin or medal can be sold if you price it low enough , advertise it well and wait for a buyer. Whether you can sell for enough to make a profit or even to recover your costs is an entirely different question. My guess without knowing what you have is that you are unlikely to make any profit.
U.S. Mint, Littleton, or anywhere else that sells the Presidential Dollar Series.
No. There are many presidents that were never even on a single coin.
The US Presidents that have their face on a coin are George Washington, Abraham Lincoln, Thomas Jefferson, John F Kennedy, and Theodore Roosevelt.
in my research i found that they are worth around 3.99 each but you will not get that amount from a pawn shop each shop will vary on price value
No, there are currently only 44 presidents in US history, including Obama.
http://www.whitehouse.gov/history/presidents/
Sacajawea, and the American buffalo
presidents in god we trust date denomination
Benjamin Franklin - Half Dollar
Value is around $3.99 per coin individually or a complete set of 41 for around $110.00
Hoover is not on any US coins. He is scheduled for a $1 coin in 2014 as part of the on-going series honoring each president. Many mints have produced medals of the US presidents which resemble coins . Some foreign countries have minted coins with US presidents on them to sell to Americans- one of them may picture Hoover.