It can vary that much on the smaller commitments of Bandwidth and Space, the issue is that a lot of the companies do not like to have just a single server collocated with them. You have a lot of overhead in quoting account managment etc that you have to deal with for just one customer.
A lot of items go into what a company quotes. Just to name a few:
- Facility they are in and how much they pay per cab/rack (for power and space)
- Bandwidth providers they use and how much they pay per meg
- Types of support they offer/or don't
- What type of server you are colocating (1U or tower)
So its no surprise the varying quotes. What I would ask myself first is: how critical is this box im locating and am I willing to pay a good price if it is. From there, how much BW do you need/or can live with, what location of the world is the colo in, and what type of hands support ($$ and 24x7) do they have. Then you can narrow down some of the quotes.