it can cost more than that sometimes...and it depends on what has to be done. I know a person who had a degree in EE but was working on a IT job(hired directly by an American company)...the lawyers suggested to sent the transcripts to another expert who compared if the degree and the job performed would match or not...In the end the total cost for the whole H1 B filing process came out to be about $8000. Lawyers charge a lot of money for their consultation. However if you don't have to do anything extra like that, it shouldn't cost so much.

Also keep in mind that it is illegal for the emplyer to take money from you to file your H1 visa. They can't take money from you nor can they reduce your salary for filing H1 B visa.