how mu;ch does it costs to get a name change down?

Your question cannot be answered in this forum.  This site offers general information and not legal advice or price information. Lawyers charge by the hour.  Therefore, the price of a name change will vary depending upon the amount of information that needs to be reviewed, reasons for the name change, whether you are able to meet all of the statutory requirements, etc.  I suggest that you confer with an attorney to discuss this matter in greater details. Best of luck~