Here's a list of some of the prices being offered for the 3DS, in the UK. Only brand new prices, no used prices. And I'm only counting those sold by the retailer themselves.
Amazon.co.uk: £129.91 (Black), £134.00 (Blue) Tesco.co.uk: £115.00 (Black), £115.00 (Blue) Game.co.uk: £139.99 (Black), £139.99 (Blue) (GameStation is a subsidiary of Game.co.uk, so their prices are the same) Play.com: £139.99 (Black), £139.99 (Blue) ASDA.co.uk: £134.00 (Black), £134.00 (Blue) Argos.co.uk: £149.97 (Black), £149.97 (Blue) Sainsburys.co.uk: £205.99 (Black), £205.99 (Blue) ---- obviously they never got the message <_<
The absolute cheapest you can get the 3DS... is £105.80, through Quidco.com. This is the equivalent of $170.78, which is mearly 79 cents above the US price.
