I think there is a lot of competition with GPS modules (core guts) becoming cheaper and smaller, plus there are a lot of people starting to create Nikon GPS offerings. I don't know about the $45 shipping charge. I can only guess that since its coming from China and it has to clear customs there are additional charges. I haven't bought too many things directly from Asia, so I don't have any experience with comparative charges.

Nikon D200 and up cameras look for a NMEA0183 v2.01 data stream to be present on the camera's 10 pin connector. If it finds the data stream it will extract Latitude, Longitude, Altitude, and Coordinated Universal Time (UTC) and embed those elements into the photo's metadata as the picture is taken. Various solutions to do this exist: 1. utilize a off-the-shelf portable GPS device that has NMEA0183 serial connection and connect that to Nikon's MC-35 GPS Adapter cord; 2. specialized Camera GPS device which directly connects to camera's 10 pin connector (e.g. Dawn Technologies N2 di-GPS - http://www.dawntech.hk/di-GPS/n2.htm, or the one above); 3. generalized Camera GPS device that is camera independent (e.g. Jobo AG's PhotGPS - http://www.jobo.com/usa/products/photogps/index.html). I personally purchased the N2 di-GPS and have been very happy with its performance.

Just what I was looking for!