I've looked at the German section recently. Well you do have to realize that there is a major price difference between the US and Europe and UK. Obviously this is going to result with even more differences when we look at country specific prices. I would say that the US would be the cheapest and that one should get their stuff from it (if you can avoid high importing tax and whatnot).
For accounts this is different. Like I've previously said, it has probably got to do with the wealth of the people (1st - 3rd world countries). I haven't seen any accounts being sold on the Croatian section (yet).
Yeah, my assumption was that buying accounts, codes, etc. That people generate themselves would typically be cheaper in local boards. However, I didn't expect that tangible goods would be cheapest in US. I figured that since many goods are produced overseas, and overseas sellers have a lower standard of living typically, they would sell items for cheaper in their local area.