Indeed, I've seen Cogent go for $800 - $1000 for a 1GE over 10GE commit.
Ignore the whole song and dance when they have to bring in a VP into the call to specially approve the pricing they're trying to pitch to you at. Those are standard transit sales tactics. Or avoid Cogent's sales entirely by working with a reseller.
This goes back to my first point in that going into the DC requires staff with very different skill sets. It's not that it's not worth it, but there's a lot of costs involved part from the per-hour instance cost.