myself i keep the 100.00 in my pocket and wait till you can buy a new mb and a stick of ram. i had an older 775 system i had for years and then built an i5 rig. the speed is like night and day. as haswell and newer amd chips are going to drop if you can wait then the older sb and ib chips are going to drop.
I can't seem to find any C2Q Q8200S, Q8400S, Q9400S, Q9505S and Q9550S used or even new on amazon or ebay, those cpus were discontinued or something?
LGA775 is ancient history by now. Most of the few remaining LGA1366 and LGA1156 CPUs have been discontinued over a year ago. Even on the current LGA1155 socket, Intel is discontinuing old parts as they introduce new ones.
Most parts are in full availability for about two years before production. It takes about a year for new parts to overtake sales of their predecessors and production to completely transition to newer parts. It takes about another year for old parts inventory to clear out. Anything you see on the market beyond that (say about a year) are leftovers and once those dry up, you are out of luck.
Core2Quads were introduced around six years ago so you are looking for parts discontinued 3-4 years ago. They would naturally be hard to find, particularly new.