Depending on the licensing options set by the publisher of the music you’re interested in, there might be no need to buy more than one copy of a score or part.
Publishers using Score Exchange can choose to allow you to print as many copies as you need from a single purchase, or require that you purchase the number of copies that you need.
The full detail of the current license for each score or part is displayed below the on-screen preview
If you need to purchase multiple copies then you can set the quantity when you add the items to your basket, and adjust the quantity during the checkout process.