These "coins" are made as a convenient way to buy and sell small amounts of silver as an investment and the price is determined by the daily metals markets. Today's paper says that yesterday's closing price was $7.00 per ounce. Most dealers will pay 80-90% of the current spot price and sell for spot plus 20-25% if you are dealing with only one ounce, so figure you could buy one for about $8-$9 or sell one for $6-$6.50. Flea-market dealers and antique stores usually think theirs are worth about twice as much when selling.
The value is only for the silver, about $35.00
That's not an actual dollar coin, but rather a silver bullion round. The coin might not have a date, but it should at least mention its weight. As of 19 February 2014, silver is worth $21.84 per troy ounce.
Indian Head Nickels (with a buffalo on the back) were only minted from 1913 to 1938, so I have to assume you have something else -- perhaps a Liberty Head Nickel (with a big "V" on the back)? A well-worn 1891 Liberty Head Nickel is worth about $3.00
It isn't an error, it is a privately minted round. It isn't legal tender and the actual design gives it no value. What does give it value however, is the 1 troy ounce of silver in it, at the time of writing silver was around $28.69 an ounce, so that is what your silver round is worth. Keep in mind that silver prices are very volatile and increase or decrease daily.
That's a one ounce silver round, so the value varies with the price of silver. As of 20 June 2012, silver is $27.90/ounce.
Most likely it is just a bullion piece worth 1 troy ounce of silver. Right now it is about $30 or so, but the price of silver rises and falls depending on the minute.
What you have isn't a US coin, but rather a privately minted silver bullion round. It is worth whatever 1 troy ounce of silver is worth, at the time of writing it is worth about $34, but the price of silver fluctuates, sometimes wildly, so tomorrow it will be worth more or less.
In 1853, a Troy ounce of gold was worth $20.67. It retained this value until 1934 when it was raised to $35.00 an ounce.
What you have is a silver buillion round. As of 28 December 2013, a one ounce round is worth $20.06.
....Its a 1 ounce bullion coin/round. These are privately minted rounds produced as an easy way to invest in silver. They are usually not dated because they are not numismatic products and aren't collected as a coin is. Rather they are just worth their intrinsic silver value. Today they are worth about $30, but it depends on silver spot price.
From your description this is not a US Mint product, it's a privately minted replica of the 2001 American Buffalo silver dollar, the value is for the silver only, about $26.00.
Buffalo Bill never appeared on a U.S. nickel. A 1937 nickel has a picture of a Native American chieftan on the front, and a buffalo (animal) on the back.