I think there are also plenty of good trials to download. I personally started with Fruity Loops, which I also recommend; extremely easy to use and the trial comes with some sounds too I think, If not, Im sure you can still use the sampler. Once you get really good I suggest dishing out some odd $50 on the full version or some 200 on the educational version of Reason. Only if you really, really, really like making music I would suggest buying the full versions, which usually cost about $400 or so :X
But yea, I suggest getting the Fruity Loops Trial for Version 8, link provided
http://www.softpedia.com/get/Multimedia/
Audio/Audio-Editors-Recorders/FL-Studio.
shtml
*Note = Apparently you can do everything in the trial version, just not save your file, but you can still export MP3, in this case I would definetly go with this.