New Orleans never struck proof coins. Up to 1964 proofs were only made in Philadelphia.
Assuming you have an uncirculated 1880-O Morgan, you'll need to have it professionally appraised. Depending on how well-struck the coin is, as of 03/2009 prices for uncirculated specimens range all the way from $55 to almost $2000. A certified dealer or appraiser would need to examine it in person because small differences in quality can mean a major difference in price.
Numismedia shows an 1881-O deep mirror proof-like Morgan retailing for about $88.
A typical (MS-63) Mint State 1880-O Morgan has a average retail value of $375.00 if certified by a known grading service.
Assuming the coin is circulated retail values are $17.00-$30.00. This date/mintmark Morgan is common.
The 1880-O Morgan Dollar, in MS-65 Grade, is so listed in the Red Book.
value for the 1887 o morgan ms 63 double stars value
Assuming the coin is circulated and still in collectible condition, the 1880-O Morgan dollar is a slightly better date Morgan with retail values of $38.00-$50.00 depending on the actual grade of the coin
The 1881-O (New Orleans) Morgan is common, retail values are $32.00-$39.00 for circulated examples.
1883-S $30 to $250,000, 1880-O $27 to $70,000, 1921-O does not exist.
Assuming the coin is circulated, the 1880-O Morgan dollar is a common New Orleans Mint Morgan dollar. For an accurate assessment of value the coin needs to be seen and graded. In general retail values for low grade coins are $17.00-$19.00, better grade are $21.00-$22.00 and coins showing almost no wear run from $25.00-$38.00. Values are a market average and only for coins in collectible condition, coins that are bent, corroded, scratched, used as jewelery or have been cleaned have far less value if any to a collector or dealer
August 21, 2009 The 1886-O Morgan Dollar in AU53 grade has a value of about $90.
The 1881-O (New Orleans) Morgan is common, retail values are $17.00-$26.00 for circulated examples.
Values are: No mint mark, "O", or "S" - about $17 "CC" mint mark - $100 if worn, $200+ with only moderate wear. Note that there are Morgan dollars and Trade dollars, but they're different coins. Trade dollars all have those words on the back. Plus, 1880 trade dollars were only issued in proof, so it's almost certain you have a Morgan dollar (the classic silver dollar most people think of)