How much does Ubuntu cost?

Ok, first of all Ubuntu is free (as freedom) and by now free (as beer). From the business page:

No hidden costs, no lock-in

Looking to escape the cycle of endless Windows upgrades? Now, there's a real alternative. No licence fees and no licence tracking overhead. With Ubuntu, you can scale your desktop infrastructure while keeping your cost down. You only pay for the level of support you need.

Download now for free ›

What this means, that the support should be supplied by yourself and the community around Ubuntu. Of course, if you have a emergency, don't expect fast response of the community, as we (the community) are all volunteers and not paid employee. That said, Canonical offers paid support for enterprises:

Buy professional support services

Canonical’s support engineers understand how important your IT systems are. Support with our systems management tool Landscape, is available to suit all levels of demand.

If this is what you are asking about then be my guest into contacting Canonical Ltd.

This site is not managed by Canonical Ltd. in any manner as you can read in our meta question:

Canonical gave permission for Stack Overflow to use the Ubuntu trademark and logo for Ask Ubuntu. A Canonical employee also assisted in the site's new design to help meet the Ubuntu Brand Guidlines.

Beyond that Canonical has made no public announcements relating to Ask Ubuntu. (So we must assume that the site is not officially endorsed by or related to Canonical).

(Note: There are Canonical employees that are members of the Ask Ubuntu community.)

That said, I hope you can get a idea where is what you are looking for.