Get one of those rear fenders that attaches to the seatpost. It's enough to keep you from getting skunk stripe, but it's not as if it's a full coverage fender or anything. Up front, get a clip on that attaches to the downtube.
Crud Catcher clip on fenders
*edit*
looks like they haven't updated their site for a while, but their stuff is still available online at a few retailers.