"DO" isn't a mint mark. The mint mark on a silver dollar for that year is on the reverse (tails) side, just above the letters "do" in the word "dollar."
If it has no mintmark it means the coin was struck in Philadelphia.
Check the back of the coin under the eagle to see if it has a mintmark, it can only be an O, S or CC, it may not have a mintmark but it makes a difference in value. Post new question with new info.
Currently a 1880 S Morgan silver dollar in MS65 uncirculated condition is worth $156.
If you mean a 1880 Carson City Morgan dollar? circulated examples run from $100.00-$300.00
A 1880-S Morgan Silver Dollar that is in a mint state of MS67 is worth: $ 450.00.
Look on the back below the DO in DOLLAR. It could be black or there could be a small O, S, or CC mintmark. Value as of June 2012: No mintmark:$52 "O" mintmark:$156 "S" mintmark:$52 "CC" mintmark:$540
If it has no mintmark it means the coin was struck in Philadelphia.
Check the back of the coin under the eagle to see if it has a mintmark, it can only be an O, S or CC, it may not have a mintmark but it makes a difference in value. Post new question with new info.
Assuming the coin is circulated retail values are $17.00-$30.00. This date/mintmark Morgan is common.
7-31-11>> Assuming the coin is circulated and has no mintmark, the 1880 Morgan dollar is very common. Values are $38.00 in the grade of VG-8
It depends on which mintmark? Post new question.
Likely $18.00-$20.00 just for the silver. the 1880 date is very common, but check the back of the coin for a mintmark, if it has a "CC" mintmark it's worth a lot more.
Currently a 1880 S Morgan silver dollar in MS65 uncirculated condition is worth $156.
Please see
If you mean a 1880 Carson City Morgan dollar? circulated examples run from $100.00-$300.00
A 1880-S Morgan Silver Dollar that is in a mint state of MS67 is worth: $ 450.00.
1880-series US $2 bills were issued as United States Notes rather than silver certificates. Please see the question "What is the value of an 1880 US 2 dollar bill?" for more information.