You could probably buy the demo itself online somewhere (though yes, DQ8 is really a good game). Personally, I didn't think it was a great demo (you get two different areas to play, one which features real time and the other which freezes while you decide your actions). If you want to try out the basics of the battlesystem its good, but you don't get to see any towns or people or the menu or the license board. If a character has full MP (they must have full) and an esper, they are able to summon it though, so it does feature some of the espers. So the demo doesn't really feature too much, but if you want to try the battle system, its good.