Yes, that is the cost which, hopefully, will only go down.
The accuracy of the sensor is directly related to the accuracy of the calibration process which you must carry out 2-4 times a day with a regular Glucometer.
This is not as straight forward as it seems, and takes some time to get it correct.
Also, the information you get from the CGMS is delayed about 15mins from real time.
Yes, I do feel a bit like a cyborg and juggling skin real estate is something I am still getting used to.
CGMS is not a magic bullet, you need to have carb counting, basal adjustment, bolus adjustment and all the other diabetic basics clearly understood, not neccessarily under control, before you might benefit from a CGMS.
If you haven't done it, I would highly reccommend DAFNE training.
Also, have a look at hypoactive.org.au to see what other Australian diabetic atheletes are up to.