I don't know what area you are in, but I have recently called two ed psychs in my area (Chicago suburbs) who are known for gifted testing and they both quoted me $500 for the WISC-IV and a report.

Also, at least one gifted school in my area will test any kid (whether they are applying or not) also WISC-IV I believe for $450.

Still pricey, but much better than $1500. I would call around and maybe try to find a private practice Psy.D. with experience with gifted kids.