If you don't want to go through the steps in the article (finding a suitable amplifier is the big hurdel), the only remaining option is the discontinued Griffin iFire:
This was THE solution but did not stay long on the market. Used, this little gem now costs most that an awesome set of modern external speakers:
You can certeinly look for one cheaper. If you can find one for under US$50, it at least sounds like a good finanacial investment!