Here is why I won't be buying.
This isn't just undercutting, this is a drastic loss leader. Selling below their purchase price in a bid to drive market share and other shopping. It's downright anti-competitive, and misleading for customers who start to expect every game to be sold at a huge loss, making real gaming shops (both big and independent alike) look like they are ripping people off.
This isn't some small retailer creating publicity to make a name for themselves, this isn't clever purchasing or out of tax cleverness; this is using market position, big bank accounts and store portfolio to get a foothold in a market in which they are usually pretty expensive (anything not brand new is rarely reduced).
Is this much different to the bus company that ran almost free buses to kill off local competition, then got rid of them and raised prices?
Happily the retailers that actually care about gamers and gaming as a pastime are too strong and have enough unique advantages to avoid being severely damaged by this ploy; but I wouldn't be surprised if it is the nail in the coffin of a few independent stores losing out on sales for the biggest game of the year.
To me it's like buying a car stereo at 75% off from some hooded 17 year old outside Halfords, you can't be that cheap and be totally trustworthy. Like paying £10 for a jacket and then complaining when it doesn't last and was made by a mistreated 3 year old in Indonesia for 12p.
Supermarkets are already killing pubs by doing this with alcohol. If we let this become the standard for games, then don't be surprised when the local stores start dying and the prices creep up.