What’s the difference between a 

Limited Edition print and an Open Edition print ?

A Limited Edition print is one of a limited number made. This could  be from 5 to 500 .  Each print has a number that looks like a fraction , for example 5/20 which is usually written in pencil  . No more reproductions will be made of the image in the future. 
They are often signed by the artist to show authenticity. A limited edition print is usually more expensive because it is more exclusive or rare.  

An Open Edition print means that there is no limit to how many prints can be produced. They are a more affordable option.