This question intrigued me so i did a bit of googling... Neppy has a spec sheet of their ROVs on their site (http://www.neptunems.com/sites/neptunemscomau/assets/public/File/pdf/15.%20Swift%20ROVs.pdf). On the spec sheet they say they have work class ROVs...
After that i found this site - www.rov.net - where they say... "The Price Range of the Work ROV systems range from $ 500,000 to $ 5,000,000"
so i guess the price is mainly driven by the type(s) of manipulators the ROV has...
NMS Price at posting:
43.5¢ Sentiment: LT Buy Disclosure: Held