Wow, that is a good deal. I'd give 6.40 for an XP rig.
I recently had a similar experience.
My local RTO shop had a Dell Inspiron One 19T for sale "as is" for 50.00. Guy said it boots to a black screen with white letters and wouldn't go any further. Windows 7.
I figure, what the hey, it has a 500 GB HDD in it, worth the 50, so I took it home, ran a repair install, voila! So, I put 8.1 on it, to use the touchscreen capability, and.....
I now have a 19" touchscreen AIO PC with Windows 8.1. I took the 500 GB HDD out and added an SSD I had spare. Nice little rig.
Pentium Dual Core E5400 2.70 4 GB ram.
But, in doing so, I managed to get the screen in a bind, I guess. When I got this thing, it had one black pixel that I could live with. Now, after my opening it up, it has a 1 pixel blue line running vertically where the one black pixel is. All in all, still a good PC for 50.00.