It would depend on the exact date, condition, mintmark, and denomination of the coin. Post a new question and structure it like this to ensure the best answer: What is the value of a <date> US < denomination>.
With so many dates it's impossible to give them all values with looking at them. However these coins are silver and are worth at least $21 for their silver content.
A silver dollar with the national motto E PLURIBUS UNUM on it dated 1880 is actually called a MORGAN dollar, most all US coins have this motto somewhere on the coin. It's a very commoncoin with a retail value of $36.00-$42.00
Please see
Currently a 1880 S Morgan silver dollar in MS65 uncirculated condition is worth $156.
Responses to questions on Answers.com are normally specific to one item. Please check for questions "What is the value of an 18xx US silver dollar?", where 18xx is 1880, 1881, etc.
There were no $1 silver certificates dated 1880. Please check your coin or bill (which is it?) again and look at the related questions for more information. Also note that nearly all US coins and bills carry that motto so it's not something that helps to ID a particular item.
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.
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.
In MS60 Grade uncirculated, a 1880 S Morgan Silver Dollar is worth about $52. In MS65 Brilliant Uncirculated, it is worth over $330.
Currently as of April 2012 a 1880 Morgan silver dollar in MS63 uncirculated condition is worth around 63 dollars.
August 29, 2009 The more common 1880-CC dollar in MS65 grade has a value of $1625. The less common Proof-like 1880-CC dollar in MS65 grade has a value of $1900. The scarce Deep Mirror Proof-like {DMPL} 1880-CC dollar in MS65 grade has a value of $11,000.