The nicest pens I've ever seen were only (only?!) a couple hundred dollars, so that wouldn't use up that whole budget. xP Maybe I've only seen cheap pens, though...
I like the trip idea, because that's one of those things I would love to do myself, but if someone gave me the money it's unlikely I would use it for that purpose.
(Personally, when I graduate, my reward to myself will be that I never have to tolerate any of the people I went to school with, ever again! Oh, I may buy myself a handbag too... ;P)