I find it interesting that while my son at level 42 gets 6 gems out of a box on happy inferno island while I get 3? When I am offered a combo pack, it contains less gold, less food but costs the same as what my son is offered. Seems like a way to keep lower level players lower. Gems cost the same no matter what level you are.

I'm not sure what system they use but the cost of those sort of things change all the time for each person. I see it often when I go from mobile to PC DragonCity. The boxes in HappyInfernal have a randomly generating number to determine output.