Is the B11AA just using that as your postcode?
Not quite as cheap as amazon but no postage tricks necessary and free delivery:
16GB Class 4 MicroSDHC €10.46.
I reckon you'd be better off with the Class 10 though.
16GB Class 10 MicroSDHC €12.61.
Only a €2 difference between class 4 and class 10.
Does B11AA work for items on Play that they won't ship here such as memory cards and such?
Some people have reported it working.