I'd scrounge two or three on eBay for that kind of money. Unless there is a "just gotta have it" combo of parts inside, that's a lot for a 133cs. You're going to want to build a 166c in the long run and the Processor cards are not interchangeable, IIRC.

Check the price/shipping total of the three I snagged in this thread, I think it's less than $75.00