ASUS P6X58D-E Motherboard. Good condition. $105 plus shipping.
http://forums.evga.com/Huge-Parts-Sale-Thread-NEWUSED-GPUsRAMCPUsMOBO-PSUs-EKWB-and-MORE-PRICE-DROP-m2182844.aspx
i7 920 is cheap, but the 1366 motherboard itself will cost you at least 70 - 100 dollars, that would put your total up to 110+.
Since you are on a super low budget, go for the i3 combo deal for 95 dollars and buy a decent GPU.
It doesn't really matter if its the international version because AT&T and other major GSM carrier are able to detect it nowadays. So, the grandfather data plan doesn't work.
From what you are saying, you must live in one of those states that does not need to pay tax when ordering from Newegg or majority of the online computer store right?
Amazon and Tigerdirect is the way to go now for me in California. Free shipping + no tax can always beat the price that Newegg has. Oh ya, Tigerdirect have bing cash back too.
If the one you have in the system was a PC2-4200, then it does not matter if you buy a PC2-4200 or PC2-5300. However, if it was a PC2-5300, it is recommended to buy another same speed or higher because it will downgrade to that speed automatically.
I think the only invoice ZipZoomFly provides is when you email them for one. Printing out the one on the website is just the order page. I may be wrong though.