Toronto Research Chemicals (in Canada) sells KDO for C$400 for 100mg.
Here is a link to TRC's on-line catalog page for KDO:
(If the link doesn't work, cut back the URL to the top level and use the
catalog search engine located there.)
I don't know who sells KDO in Europe.
Hope this info is helpful to you.
A.J. D'Ambra, Ph.D.
Research Test Development
Pasteur Merieux Connaught USA