ebay might be the only way. however its a lot cheaper then they were a while ago. I sold my t7600 on there for 450usd a year ago. Now they've gone down a lot since i7 came out.
Try looking for the t7600, its not only faster but you might find it fairly cheap.http://cgi.ebay.ca/T7600-Intel-SL9SD...item4cef1d50d9
and upon looking I found the cheapest (I'm including shipping) cpu I found on there for by it now. There's a few auctions going on for them too.http://cgi.ebay.ca/Intel-Core-2-Duo-...item563bf5e38b
you're probably not going to get it any cheaper than 80 if you look hard enough, if you wait a year you can get it for 40-50 bucks.