As stated you are the only one that can decide if its worth spending money trying to get Data back.
There are many ways to try and retrieve data, some of which depend on what sort of files you are looking for. The last quote I got was "between $600 (minimum charge) and $2000" depending on what they needed to do.
I have had a lot of success using Sumuri Paladin (a Digital Forensics Bootable DVD aimed at MacOS) and creating a bit stream image of the External Disk (doesn't need to be mounted) then running "Photorec" and other utilities to see what is recoverable from the image file. Photorec is aimed at recovering Image Files (jpg, png, mp4, mov etc) but can recover .doc, .pdf, .mp3 etc as well.
Another option would be to create a PartedMagic boot disk and see what it finds when you repair the disk. Though when using disk utilities, if they don't work they can make things worse. I always take a bit by bit image of the drive using Paladin first, then you can run utilities on the image rather than the disk itself. Its what we do when forensically checking drives for evidence.