The demo of Baldur's Gate sold back in 1998 for a few bucks. It contained the first two chapters of the roughly six chapter adventure. This was way the hell back in 1998 when broadband connections such as the glorious cable modem were less common. Since few people are willing to spend ten years downloading a 250MB demo on a dial-up, they decided to release a cheap demo and sell it in stores. (Releasing the demo of any Bioware game would require uploading the entire Bioware engine, so needless to say, you wouldn't have many takers back then.)