Lightweight water resistant pants?

Can anyone suggest a nice, light weight water resistant set of pants? I've seen some waders and stuff from cabelas, but I'm looking for something a little lighter. We had some really nice ones issued to us in the Coast Guard through Life Saving Sytems, but man they are pricey. They weighed next to nothing and I swear were made of nothing but formulated Rain-X. I just having a soaking wet butt for a whole day out

I'm hoping to spend under $100