Many music websites offer free printable blank music sheets, such as Blanksheetmusic.net, Flutetunes.com and Music-paper.com. You can download these files as PDFs that you can then print.
The music sheets, also called "staff notation" sheets, are also customizable depending on the instrument, clef or time signature desired. For instance, you can download sheets formatted specially for the drums at Learndrumsforfree.com.
The choice of sheet music varies between a four-hand piano composition, a singer-and-pianist score or a large brass band. Most sites let you customize your download to suit your needs. You can also customize options such as color, orientation and indentation.