I echo what most people are saying, dry suits are worth it!
I used to use neoprene which for rafting is just too uncomfortable and restrictive. Plus in order to be warm in neoprene when it is cold or after a swim you have to pee your suit which isn't so bad if you have been drinking a lot of beer, I guess!
I scored a Kokatat Meridian Gore Tex dry suit on craigslist a couple years ago for $400! I probably use it 10-20 a year and it was so worth the investment. Just took a swiftwater course in Carbondale, CO last weekend in the snow and rain and if it wasn't for the drysuit I would have been miserable.
Search on craigslist, I bet you can find something or even rent from Kayak Academy | The Elite School For Kayakers And The Kayak Gear Store With Everything You Need
if you want to try one out...
Stay dry, stay warm!