Second the pay via committed/burst rate (per-Mbit) instead of GB.
If you indeed have 1,000TB of bandwidth usage, you're looking at around 5Gbit of usage (assuming a fairly aggressive 200GB per Mbit @ 95th percentile efficiency). This number can change considerably depending on your traffic, but 5-6Gbit is probably pretty safe.
So yes, you could do much better.
Hit me at
[email protected] and I'd be happy to get you an aggressive quote.