If you are a music composer, whether you are amateur or professional, music notation software can save you time in laying down your sheet music. If you don't have a large budget for music notation software, you can get basic packages for free or cheap that will allow you to perform basic notation and printing functions.
If you have a bit more money to spend, you can get a professional-level program that will streamline your composition process by offering resources for transposition, composition with a MIDI keyboard and many other useful functions.
Finale Notepad is a free program offered by the professional notation software manufacturer Finale. Finale is a bare-bones notation program that will allow you to place one track of notation on a page. Using Notepad, you can also add basic markings such as tempo and dynamics that will help a reading musician better understand how to play your piece.
The full version of Finale is a beast of a program that offers an overwhelming multitude of tools to help you refine, adjust and clean up your music manuscript. Using Finale's MIDI capability, you can write your piece with a MIDI capable keyboard connected to your computer via an audio-MIDI interface. Most newer professional musical keyboards are equipped with some way to input, through or output MIDI, allowing you to string multiple devices together in your MIDI chain. (In MIDI, "through" describes the process of running the a device's feed both in and out of another device to form a device chain.)
Sibelius software is popular notation software that is easy for composers to learn. Sibelius offers a limited demo version on its website to help you learn to use the program. The demo version of Sibelius will not save your work, but it will allow you to get an idea of the functionality of the notation program. Sibelius also offers a 30-day trial version with the full program functionality. If you just want to print scores from the Internet, Sibelius offers a freeware plugin, Scorch, which allows you to view, download and print scores you find online.
Noteworthy Software is a notation suite for Windows. According to the Noteworthy website, Noteworthy is designed to help you "create, record, edit, print and play back your own musical scores in pure music notation." Like Sibelius, Noteworthy offers a free demo to help you decide if you like the program. It also offers a free viewer that can help you view scores downloaded from online sources.