Soundfonts buddy. That is absolutely the best way to start, because it's free. It is sort of considered old technology, but soundfonts can be several hundred megs or even over a gig in size nowadays due to software soundfont players.
2 soundfont players I recommend are "synthfont" and "SFZ" soundfont players. look them up on google.
Then, to get good quality soundfonts, start at:
www.sf2midi.com www.audioshots.com www.hammersound.net Many many of these samples are in the public domain. Some however, are rips from commercial products and that is rather a sticky subject from time to time. But as long as you are just a home hobby musician I shouldn't think it would make a whole lot of diference either way.
Some soundfonts are instrument specific, and some are entire GM collections.
Both Synthfont and SFZ can be used as stand-alone apps, or as a vst plugin off a sequencer like Sonar or whatever.
Enjoy