Ask any friends, someone is bound to have one. If you know anyone who has a PS3, the controller chargers work on BlackBerrys. Most external hard drives use mini USB cords too.
I actually got lucky with this...I bought my 8330 used off ebay. It didn't come with a mini USB cord, However, my Motorola Q used the same thing, so does my PSP, and my dSLR. Also: Ebay sells trackballs for relatively cheap. And if you need the cable, get one there too. It's pretty cheap as well.