1922 is the single most common date for Peace dollars. Current retail prices are in the $15 range, so expect to get about 2/3 of that from a dealer. You might be able to get more if you go the eBay route but you'd need to balance the extra $4 or $5 versus the time needed to post and sell.
One of those "We buy gold" places would probably pay no more than about $8 at current (10/2009) silver prices.
The high relief 1922 Peace dollar is a Proof only issue coin and the design elements protrude from the background higher than usual and above the rim which causes the coin not to stack well and is impractical for coinage. Most were melted at the Mint and the ones that still exist are very rare. Likely less than 20 examples still exist. If you can find someone willing to sell an example, expect at least a $60,000.00 price for the coin.
A 1921 Morgan Silver Dollar can be purchased from coin dealers. Alternatively, as the coins are not especially rare, there are many available to purchase on eBay.
You could sell it at a coin collector or on eBay.
Better check your dates again. The only U.S. half dollar with a 1922 date is a Grant Memorial Commemorative. In circulated condition, it's worth about $60. If you have the variety with the extra star, then about $450
Just type in 1922 Peace dollar on your browser and click images.
1922 is the most common date for a Peace dollar, values are $14.00-$19.00 for average coins.
You can't. 1922 Peace dollars are common among collectors and retail for about $15. A dealer will pay wholesale, about 30% less.
$27.
A 1922 P brilliant uncirculated dollar peace dollar is worth about $200.00. It is 90% silver and 10% copper.
1922 Peace dollars were minted in Philadelphia, Denver, and San Francisco.
You can sell them to anybody, but I suggest finding a coin dealer in your area. For the year 1921, two types of silver dollars (Morgan and Peace) were issued, and each is a separate series of dollar coins. The designs and values are very different. The 1922 dated coin is a Peace dollar, but it is the most common date of the entire series. They need to be seen for an accurate value.
The 1922 Peace dollar is very common. Circulated examples are $30.00-$36.00. Typical Mint State coins are $38.00-$43.00
A 1922 dollar with the word "Peace" on the back would be a Peace dollar rather than a Morgan dollar. "Morgan" refers to George T. Morgan, the artist who designed the silver dollars minted from 1878 to 1904 and in 1921. There's more information at the question "What is the value of a 1922 US silver dollar?"
It's NOT a LIBERTY dollar it's a PEACE dollar and the date 1922 is the most common of all Peace Dollars with values of $14.00-$19.00 for circulated coins