Originally Posted by Wrider
See how in the middle it's flat? That comes from lots of straight line miles. Then see how the sides leading up to the flat spot are straight instead of curved like a tire should be? That's considered cupping. Sometimes it gets bad enough that it actually gets to be concave. Typically caused by under inflation or bad suspension settings.
That tire isn't showing any signs of cupping or feathering. It's flat as hell in the middle, but that's just from straight line commuting. I'd be more concerned about the tire if it was actually cupped:
Regardless, he does need to replace the tire fairly soon, IF he decides to bite the bullet and purchase it.
Relative to the op, I would wait and see what other deals pop up if you can't haggle him down a couple hundred more.