Don't know where you live but here in Washington after at the ind of summer the surf shops sell there rental suits. It's cold in that water even in summer so all they have is dry suits.
Cheap and drysuit are two words that never exist together. Even a good condition used DS will cost $300 minimum. That would be a well used suit. Check Flee-Bay, craigslist and area dive shops to see if any are even available. Lastly, used drysuits can be a nightmare. Replacing a zipper can cost several hundred. Replacing seals can be $50 - 100 each. Patching pinholes can be cheap but takes a long time if doing it yourself.
your best shoot would be going to your local scuba shop, they know divers that would have a drysuit . or have a used one from the rental rack. But you can buy one under $500. Sorry to hear about the job , I hope you and your family have a great 2011.