Funnily enough that's almost identical to me. I just grabbed S3 part 1 today because I saw the box in HMV, it's been there for ages, and just had a glance online knowing that part 2 was coming out soon. Then immediately realised there weren't that many of the box left.
Gridman as well had that good deal. I'll have to briefly pass with Zombie Land saga for this sale and instead grab it from Zavvi though. Got a 10% code there, and while it might not be as good as 20% it does mean I won't have to pay for it until it ships.
Think that's bad, I actual had a copy pre-ordered. Then after a few days after the release they finally cancelled my order saying they couldn't source anymore stock. Had to hunt the stupid thing down at a ridiculous cost, and even then barely grabbed one before the price shot up even higher. Gave me a lesson though. If it's a series I think I really want, order immediately. It'll cost more down the line otherwise if it is popular and it goes out of print.