Hoover & Strong has a chat function on its, but you have already contacted them.
http://www.answers.com/Q/How_much_does_mercury_cost_per_kilogram does not contain a price, but it does nicely summarize the "issues" surrounding the possession of liquid mercry.
You might try a search in the town where your niece lives. Look for "hazardous waste" or something like that. … Read more