Kindle 3G vs. Amazon.de Pricing

I’m looking for a factual answer, so while I think I’ve been ripped off (they tried, anyway!), maybe someone can shed some light:

I checked Amazon.de for an electronic copy of Adam Levin’s* The Instructions *yesterday, since the bloody hardcover is too much to carry around. They had a Kindle copy for 6,81€, a bit less even than I was willing to pay. I didn’t place the order immediately, and in the evening remembered to so and tried to do it from my 3G Kindle. The copy there was 12,50€! I figured I’d check if the price had, for some reason, gone up, but it remained at 6,81€ on Amazon.de.

Does Amazon rip off its 3G customers, or was this a glitch? I’ve already paid the 50€ or so premium to HAVE 3G, so I’d be pretty pissed if this was a regular “you’d not 3G it if you didn’t really need it”-silly customer surcharge!

Which Amazon region is your kindle registered to? Maybe its a .de vs .co.uk (or wherever) pricing differential?

Just had a quick looksee, the first return on Amazon.de for the instructions is not by Levin and is priced at 6,27, the 2nd one is and is priced at 12,24 which is comparable to the price on the UK version (where it is the first return for the search)