Well the weird thing is, there was one on ebay italy for a while but it did not sell.
Here is one that went cheap
http://www.ebay.com/itm/PROTOTYPE-2-...ht_3852wt_1185
Mine i got also under a 100 euro.
However, the game turned out quite well, and there seems to be a fanbase there. Its also quite a nice kit! Would say around 100 euro would be fair.