If I want to return a non-trackable package (i.e. a letter) from Denmark to Germany, it will cost €6.5 for 500g. Not too bad, but if I want it registered (signed by recipient), I'll have to add €10 to that. Trackable package is €24. For some reason it is cheaper to ship stuff from Germany to Denmark than it is internally in Denmark.
Edit: Polish mail is also quite cheap in my experience. I've bought from Polish sellers a few times on ebay and postage is among the cheapest I've seen.
A similar example is that if I want to take the train from Sealand to Jutland (east to west Denmark), it is cheaper for me to go to bahn.com (German Railway), buy a train ticket from Copenhagen to Germany and just get off in Jutland, than to buy the correct ticket through the Danish Railway. Silly, but that's how it works here.
And to stay a little on topic, I can add that I have just tested the fixed ACA620 that I received today, and after 6½ hours of memtests and a few games, it seems like the instability problems have gone. So everybody go get your ACA620s fixed today.