i paid about £397 for mine from comet just before xmas, but speak to jon_r as he said he saw one the other day for £350.
ive found mine to be helpful...even more so with the camera and POI add ons, and its very transferrable between vehicles because of the suction mount thingy.
my only gripe would be the fact ive had to spend another £50 on an external antenna due to the windscreen in the clio, but i knew that before i bought it really, so cant complain too much lol.