What costs more when buying a package?

Say I already have a web account and I want 250 GB more B/W

How much should I be charged?

You should be looking at around $60 per month. :)

$40+, also depends on webspace given.

it depends on
- your network: single-homed or multi-homed
- your support: do you support customer yourself, or you have a support team

it depends on
- your network: single-homed or multi-homed
- your support: do you support customer yourself, or you have a support team
What??

How do you figure what you said has anything to do with him/her getting 250 GB more B/W?

if you are in colo environment, you will see the different between price of single-homed and multi-homed bandwidth. A big difference, I can say :)

what I said is just a part of fee to manage his business. I guess you are managing host yourself, so you dont know about the business fee: tax, labour, office... that's giving you an idea to calculate how much for a hosting package: space, bandwidth, system resources...

Agreed, about the business costs such as overhead etc.

Looks like your a host so with that look at a small server to start (about $70 a month if you look around) it may not be great and you will have to put some work in. Either that or a large reseller, but it will depend on the amount of disk space required and the facilities (root access, control panels, etc.)

Say I already have a web account and I want 250 GB more B/W

How much should I be charged?

It depends whether your current web account is on shared, reseller, vps or dedicated. Price varies as you go for higher servers.