Wow, you're getting ripped off.
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.
I wish the industry would stop quoting prices they way we do (USD/Mbps, so e.g. $1.20/Mbps); Gbps is probably the right unit now, and it may make more sense to invert.
But there are lots of terms involved in a transit contract; unless you're buying tens of gigs, crossconnect, port cost, commit, etc. may be more meaningful than per-Mbps cost. And pricing often depends greatly on exactly where in a city you're buying (at IX, carrier neutral facility, etc. will be cheapest; off net building or monopoly building will be most expensive) -- and of course Cogent transit vs., say, Level(3) transit are only superficially the same.