If you are just getting started in Digital Music, the two essential software programs you need to get are a sequencer (to record and play the notes), and a software sampler (to create the actual sounds made by each note). With just these two applications and a Computer - you can start creating your own original music...

Here are two affordable options we recommend:

Cakewalk Sonar Home Studio

The sequencer is the 'heart' of the modern recording studio and is central to everything you do. If you are just getting started and want an affordable, full-featured sequencer with pro features... Check out Sonar.

It comes in many versions according to your budget, but the 'Home Studio' version is perfect for the beginner and has all the professional features you need to get you started.

MAZ Sound Tool's Vsampler

The software sampler is the second essential element of any modern recording studio. It allows you to create music using 'virtual' instrument sound libraries and allows you to create backing tracks that sound like they were recorded in a studio using professional musicians. Check out Vsampler3.

It supports a wide number of formats and has professional features such as sample streaming and RAM optimization.

There are also a few free programs available...

Kristal Audio Engine

Audio sequencer with ASIO recording, MIDI, and effects plug-ins. Free for personal use. 

sfz

Soundfont player (VSTi) which is part of Cakewalk's Project5 software package. Currently a free download.

ACID Xpress

Sony's free ACID loop player, which includes MIDI and Audio sequencing functions.

Linux Sampler

Open Source Sample player that runs on both Windows and Mac platforms. Plays GigaStudio format libraries.