Hi Molly 525,
We went in April, and we took about $40 of the currency for each country. We found that a few stores in the shopping district in the old town in Stockholm accepted dollars. We do independent sightseeing, so we found that all of the museums and attractions take credit cards for purchases over $10 U.S. each. If you leave the country with extra paper currency, you can exchange on board the ship, but you'll lose about $6 U.S. per transaction, and the exchange rate is not very good. We recommend exchanging large amounts at a local bank if you need to do that. We found that ATM machines were readily available in every country except for Tallin, Estonia. How much or how little you will need depends on whether or not you need to do independent sightseeing, which I highly recommend that you do using the walking tours on the www.frommers.com
web site. English is widely spoken in all of these countries, public transportation is inexpensive and easy to use, and you'll have a great time exploring on your own. I hope you won't let that rude comment you received without provocation from the English Cruisers to affect your desire to solicit info on the message boards. Most of the site users are friendly and not nasty. If you need any additional info, please do not hesitate to let me know. It's a wonderful trip, and I hope you have a great time!