When you're starting out making your own music with a little or no knowledge at all, it's better to begin with a software that is easy to use, but also has a good high quality output. There are not much programs out there that satisfy these conditions. To name the two I made good experiences with, DUBturbo and Fruity Loops, they both fit into this category. They differ in their prices pretty much though. While DUBturbo has a comparatively low price of about 50$, for Fruity Loops the standard price is 199$.
It's more lucrative to start with DUBturbo. However, it's up to you to choose a program that satisfies your needs most and suits best for your style and music genre. I'm sure there are more good programs on the market, so take a look around by yourself if you don't like DUBturbo or Fruity Loops. For me as a hip hop and house music producer, DUBturbo is an ideal solution. It has everything you need to produce hip hop beats and the black club beats which are getting more and more popular right now. You have all the drums and percussions, synth sounds, samples and orchestral instruments you'll need in order to produce nice hip hop beats. For electro and house music, I recommend Fruity Loops, but you would have to download a few external VST-plugins, like Albino and Blue from Rob Papen for example, to have really good synth sounds.
For the start, before you spend money, you should download a free demo of the product you consider to buy. Experiment around with the software and find out if it suits your needs. The key is to have a good look on the program itself, but also on the features it includes, like VST-plugins, soundfonts, drum packages and effect sounds. You'll need all of this to produce good sounding music, and if these features aren't included, you'll have to buy them and spend much extra money which you could use on buying hardware like a keyboard or an MPC for example.
You see, choosing the right software is very important and will save you much time and money on your process to becoming a successful producer. DUBturbo and Fruity Loops are just two of many programs out there, but they happened to be the two I had the best results and most fun with. If you decide to make your own music now, the software is just the first step, but if done right, it's a big one. To get further information on this topic I would like to offer you to read my other articles and to take a look on the programs I mentioned. It's worth a look!