Yeah, donationware or giftware would fit nicely
I also never registered anything because of lacking of money, but there's one amiga game I would LOVE to have registerd in the time, and now I can't find the author anymore..
the game is Tanx 'n' Stuff, one of the best multiplayer games ever done... I've already posted about it in many boards, and it seems like NO ONE ever registered that game..
I am also thinking about registering Music Maker, if the author sells it to people living in the west (it's a japanese program).. it's very cheap and it's very usefull too... (and it has been translated to english