Logain Sedai
Baronet
I got mine to level 9 only and I bought some diamonds (I don't know how many but not so much). I must say that I did not try very hard because I could not play much for almost one week. I think I will play better on the live worlds but I won't spend diamonds and it is OK for me, because the building does not need to be at level 10 to deserve a place in my cities.