Additional IP Address $1.00/month each -- Additional Bandwidth $0.50/Gigabyte
1 Mb/s = 2592 Gb/mo (30 day month). Assuming a B = 10 b (parity, etc.) then that's 259 GB/mo. If we only use 9 GB/mo, then there should be plenty of headroom - unless the other sites on knight use an awful lot more than we do.
The unmetered aspect might be more appealing than the 1000 GB/mo case, but I don't know for sure.
Boxley or broom might have some more insight on this.
Cheers,
Scott.