Just a simple practical tip, that's all. The two times I can remember buying batteries in Europe, once in Loughborough, England, and the other time in Amsterdam, I've just about left the store in tears. Accounting for the exchange rate in both cases it came to about $8.00 for 4 AAs for name brand batteries. In the US a typical full price would be about $4.00 for 8. If you're traveling from the U.S. to Europe, take a long some spares. And if you're visiting the U.S. from Europe, consider taking back as many as your luggage allowance and scowling customs officers will allow. F'real, though.
Disclaimer: I realize that generalizing two high street stores to an entire continent is so, like, Yankee gauche, but dammit, it's easier to sort the world out that way... Hmm. I wonder how many people use that excuse to form their impressions of the continent of Africa.