I do not know how much you know about coin collecting and the business so I will be rather detailed. How much a coin is worth is dependent on the type of coin and the coins condition. First, I will examine what type of coin you have before I answer what I mean by type of coin and coin condition. After that, I will list the blue book value of the coin, that being the value a dealer will pay you to purchase the coin. This is opposed to red book value which is the value of the coin a dealer will charge you to buy it which would be more. So, I am really listing the minimum price the coin is worth. If you openly auction it, chances are high that you will get more than that minimum price.
The type of coin you have is a Morgan Silver Dollar. It is named after George T. Morgan who designed it. His initial M is found near the neck on the obverse or heads side at the last tress and also appears on the reverse or tails side on the left-hand loop of the ribbon.
Coin type can refer to a number of different things, the denomination value of the coin, the mint that produced it, the metal content inside it, etc. For your specific coins, the only difference should be the mint that produced it. 1892 Morgan Silver Dollars were produced by four different mints, Philadelphia, Carson City, New Orleans, and San Francisco. You can identify the mints that produced the coin by the mint mark. Philadelphia is identified by the absence of a mint mark. Carson City is denoted by CC, New Orleans by O, and San Francisco by S. Mint marks appear under the tail feathers of the eagle between the letter 'D' and 'O' in DOLLAR on the reverse side of the coin.
The condition of the coin is a bit trickier and is subject to interpreting opinions. Coins are graded and roughly placed into eight different categories on a scale of 1 to 70, 70 being the best and 1 the lowest. The categories are About Good (AG), Good (G), Very Good (VG), Fine (F), Very Fine (VF), Extremely Fine (EF or XF), About Uncirculated (AU), and Uncirculated (MS or UNC). MS stands for Mint State and is used interchangeably with the term 'Uncirculated.'
Here are some general guidelines for grading. I've tailored it to your specific coin in some instances.
About Good (AG-3): Coin is very heavily worn with portions of lettering, date, and legend worn smooth. The date may be unreadable.
Good (G-4): Well worn with many features flat or faint in areas. All lettering and the date, however, is readable.
Very Good (VG-8): Well worn with main features clear and bold, although rather flat.
Fine (F-12): Moderate to considerable even wear. Entire design is bold with overall pleasing appearance.
Very Fine (VF-20): Moderate wear on high points of design. All major details are clear. On Morgan silver dollars, two thirds of hair lines from the top of the forehead to the ear should be visible. The ear will be well defined, but the feathers on the eagle's breast will be worn.
Extremely Fine (EF-40): Light wear on design throughout, but all features sharp and well defined. Traces of mint luster may show. On a Morgan Silver dollar, all hair lines will be strong and the ear bold. Additionally, the eagle's feathers will be all plain but with slight wear on breast and wing tips.
About Uncirculated (AU-50): Traces of light wear on many of the high points. At least half of the mint luster is still present. On a Morgan Silver Dollar, a slight trace of wear will be present on the bust shoulder and the hair left of the forehead, and on the eagle's breast and top edges of the wings.
Uncirculated (MS-60): Has no trace of wear, but may show a number of contact marks, and surface may be spotted or lack some luster. On a Morgan Silver Dollar, there will be no trace of wear, the mint luster will be fully present, but the coin may be noticeably marred by scuff marks or bag abrasions.
Now, we get to the juicy part where I list the blue book value prices. Here goes:
1892: VF-20, $13; EF-40, $15; AU-50, $40; MS-60, $85; MS-63, $210; MS-65, $1750
1892-CC: VF-20, $125; EF-40, $220; AU-50, $300; MS-60, $750; MS-63, $1200; MS-65, $4600
1892-O: VF-20, $13; EF-40, $15; AU-50, $35; MS-60, 85; MS-63, $165; MS-65, $2300
1892-S: VF-20, $50; EF-40, $140; AU-50, $1000; MS-60, 16500; MS-63, $33000; MS-65, $100000
The base silver metal value of the coin is $12.66. For this reason, no grade conditions are listed below VF-20 although you can assume there are all also $13.
Chances are you have the cheaper varieties in the poorer conditions. But, if you believe you have an 1892-CC or a coin that is in a mint state or uncirculated condition, you could possibly get rich quickly. In this instance, sending your coin in to get professionally graded will enhance and further increase the value of the coin. Look for Professional Coin Grading Service (PCGS), ANACS, or Independent Coin Graders (ICG) if this is the case. You have at least $143 minimum price worth of coins here.
Yeoman, R.S. Handbook of United States Coins, 2010. Edited by Kenneth Bressett. Atlanta: Whitman Publishing, 2009.