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.
Pawn shop.
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
Sacajawea, and the American buffalo
presidents in god we trust date denomination
Benjamin Franklin - Half Dollar
No, there are currently only 44 presidents in US history, including Obama.
http://www.whitehouse.gov/history/presidents/
Value is around $3.99 per coin individually or a complete set of 41 for around $110.00
Try a coin dealer or take it to a coin show.