I got my nieces the reed diffuser scent things for Christmas at the insistence of my 21 yo daughter. DD is an RA at the college she attends, and said they're the big thing in the dorms. Surprisingly to me, they were a huge hit with my nieces - 16 & 19. SIL said they'd both asked for them for Christmas, but she didn't get them.

I found them in very pretty cut glass bottles at Ross or Marshall's - both stores are in the same complex, and I can never remember which is which.