Money

It is simple and easy --- the best exchange rate will always be a debit card at a bank owned ATM in country. ALWAYS use the local currency. Do all transactions in local currency. There is a thing called Dynamic Conversion where an offer is make to do the transaction in dollars but the exchange rate will be less favorable. You will not need a lot of cash on the Viking cruises so maybe get a hundred euro and then other local currency as needed. In Hungary most items will be priced in both euro and forint but generally the forint will be the cheaper price.

Not sure if this still holds true but when I was there in 2016 I was able to get good exchange rates in a hand full of small exchange businesses. Before I used them I compared their rate to the going Euro/dollar exchange to be sure theirs was close to it. I was very surprised that they did not charge me a fee on top of the exchange and I did not pay for an ATM fee if I had used the ATM. Of course that was 6 years ago when the euro was much stronger than it is now and expected to get stronger. Pay in forint if you can so that local businesses don't have to pay a fee for accepting debit/credit cards.
I'm guessing that the cruise company would prefer that you use your debit/CC to pay for services in the ship.

Don't waste your time on exchange business. They will never beat the interbank rate charged by the credit card networks. The credit card networks will always be less than one percent above the interbank rate at that moment in time. The strength of the euro has nothing to do with the exchange rate.

Frank, I do the same thing except when I was in Budapest. At that time I had euros in my pocket and needed to exchange them. That was then and right now I don't know if it holds true. At that time my debit card charged me ATM fees and foreign transaction fee.

There are many debit cards that are essentially free of extra charges. My local credit union that I use allows for 7 free withdraws per month and then a $1 charge per withdrawal. If you were exchanging euro for forint, you paid a premium somewhere. Nobody in the money business does anything for free -- nor should they.

As previously stated use only bank owned ATMs, there are ATMs that are not associated with a bank that will hammer you with fees. As for debit cards Schwab and Fidelity both have money market funds with debit cards associated with them. Both refund the transaction fees. Just decline the DCC that is offered, just do the coin of the realm. As for your original question, most places in Hungary take credit cards, I would not get more than $100 worth of forints.

Note that Frank said "Bank ATM" not to be confused with the EURO brand ATMs all over town which dint give good rates and charge fees. EDIT: Sorry Ed, Missed your comment

But for a short stay I don't sweat a few dollars here and there so I never say "never". I needed cash last week for a particular "vendor" that didn't take cards, I was running late so I used the EURO ATM near where I stay.

Yes, if you need to unload some Euros the exchange houses will do you much better than trying to pay in Euros. Again, your loss will be a couple of bucks on 100 euro. So what.

Where 99% of tourists go, credit cards will be accepted, so maybe 10,000 forint in your pocket for peace of mind.

Finally, bank ATMs are almost always in a glass entry lobby to the bank. Often you have to swipe your card (any card) at the door ... door swings in.