That's about the going rate for fork and frame. Prep and one color (usually the solid std colors). Prices will vary even in the same area...some pay higher rent or do a better prep. You would need to ask what they do (masking threads, etc). Would pay extra for a clearcoat to make the paint really look deep or go with any of the candy colors. Here's some pics of a few of the different colors:
http://powdercoatingit.com/Bicycles.htm
http://powdercoatingit.com/