I am level 27 and the only item in the shop worth buying from my point of view is the 10 licenses. but only if i can buy gems from other players with in game resources. all the items in the gem store seem to be WAY over priced except the 10 licenses. for example 100 settlers for 945 that is 10 bucks and this will only work once. for licenses they are 650 which is over the 5 dollar but just under being able to get 2 with the 10 dollar so lets say 10 dollars. that is ten buildings which keep on giving.
