First post so hopefully done this correctly.
Came across this by accident. Grand theft auto 4 (xbox 360) Is coming up as £17.59 for 1 copy but when you get to the basket at checkout and change the quantity to a multiple of 2 it means it works out at £10.50 per copy.
Also Sega mega drive ultimate collection (xbox 360 + PS3) has a similar glitch. £17.59 for 1 copy, change the quantity to a multiple of 2 it means it works out at £15.00 per copy.
You can pick and mix between games that are £17.59. A leftover from the 2 for £30 days??
Also here's something interesting. If you play around a bit you'll find a few other combo's.
e.g. GTA 4 (£17.59) + Call of duty 4 modern warfare (£29.99)
= £33 when bought together (xbox 360)
Hope someone can make use of this.