Hi @skaur ,
I don’t know what the cost would be, you would need to contact a reputable, professional laptop repair service and ask them.
If you wish to try repairing it yourself then here’s the [http://h10032.www1.hp.com/ctg/Manual/c03659338.pdf|maintenance and service guide] for the laptop. Go to p.119 to view the necessary pre-requisite steps and then the procedure to remove the display assembly. It is during this procedure that the hinges can be accessed.
On p.38 Item #5 you will find the part numbers for the different types of hinges available, depending on the different types of LCD panels that can be used in the laptop.
Search online using the appropriate ''part number only'' to get results for suppliers of the part.