Um, why don't you just get either FamiTracker or the other countless free trackers for chip music, or one of the many, many free chiptune VSTs or soundfonts?
There, that link has links to free trackers and free soundfonts and plugins.
Making music is what you make of it. WAVs are the biggest file size, with everything else being far smaller. Having your music files as oogs, mp3s, or aacs will make their use of resources negligible.