Great question!
My 15-year-old son bought a $55 uke with his first paycheck from his first job this summer. I have no idea why he bought it, I guess he just thought it was cool. He doesn't know how to play it or anything. Anyway, I started looking at books and websites for him to help him if he wanted to learn, and I got interested in it myself! Mine came in the mail this past Tuesday and I already have so many songs printed out to learn that I have a 3-ring binder all made up and everything. I was playing "Hallelujah" pretty evenly by the end of the first day. That was encouraging.
Much different from when I tried to learn guitar. I'm only 4'11" and my hands are very small, so I had a hard time reaching chords and getting comfortable getting my arm around the instrument. The ukulele fits me quite well! (I also have a smaller guitar on layaway, but that's another story for another forum...)