That seems like something you should be able to figure out for yourself.
A simple plan would be to go to the offers forum and compare offers of similar packages.
Is the 2000GB of bandwidth single-homed, multi-homed, using what providers? The mix and quality of bandwidth will greatly change the price.
"with management" sounds questionable as to what level of service one would get when you're asking this sort of question. Is there live online support, email support, phone support, a ticketing system, any sort of control panel included?
I could say any number regarding a reasonable price, but if that number is less than you're paying for the server yourself... it's rather useless to you. (Unless you're simply fully reselling and only hoping to take a commission).
Are you doing the management, or simply reselling someone else's service for that as well?
Figure out how much work you are doing yourself and figure out how much that work costs you to perform.
Figure out how much of a profit you want to make.
Add those numbers to the cost you're paying... and you have a start.
Compare that number to comparable offers. ?
Thanks for your input SLA Will be a high service as there will be email and support desk inplace 24 / 7 it would be mixed bandwidth houses in redbus interhouse. Please forgive me for my ignorence but i rent servers in america but want to move business more to home and also offer a great higher class of support being near london and have hands on access to my servers. Cpanel would be included i was thinking along the lines of £120.00 per month and then introducing 1st and 2nd month offers etc. I really dont know if this is over the top. Worrys me with compertition selling at 49euros etc.