Should I book activites ahead/foreign transaction fee on the VISA?

I use a Capital One card so there's no fee but even if I didn't I like to pay for things ahead. If there is a special deal or online discount so much the better ! The deal will probably save you more than you would spend in fees anyway. (If you paid on-site with the card you would be paying the transaction fee anyway.)

Neglecting the fact that you have a rotten Visa, three bucks on a hundred is not exactly a deal-breaker.

I'd suspect that the bus tickets are going to have a foreign transaction fee no matter how you charge them since those things get applied at the source that takes your money -- you'll still pay them, I bet. I have no idea what the internet discount fee is, but a family day pass for Dublin buses is either five or ten euros (forget which). If you pay for it with cash, there's no exta fee (unless your bank charges for getting money out of an ATM -- foreign banks do not.

Personally, I think too much is made of the FTF business. If you charged three grand, which is really hard to do if you use cash, that's less than a hundred bucks, even at your rate. We generally travel for a month at a time and use mostly cash. FTFs for the last trip were less than twenty dollars and that was mostly for gas.

Just to get your mind churning, we're a couple of weeks back from about a month in Ireland. We had reservations only for the first and last nights (Dublin). We went all over the place with no reservations. My wife picks where we stay whenever we decide to stop. B&B's are plentiful and their economy sucks -- it never took her more than fifteen minutes to find a place and she usually got ten to twenty percent off the 'normal' price just for asking (and paying cash) and she generally found some pretty spiffy places. (Okay, there were a couple of rooms above a bar but they were super deals and it sort of added to the ambiance -- we've stayed in a lot worse in other parts of the world.)

For things as inexpensive as hop-on hop-off bus tours, it's better to wait til you get there and pay cash.

Use your ATM/debit card at ATM's in Ireland to get your cash.

Reserve your credit card for larger expenses, such as hotel or rental car bills.

Your VISA will charge an exchange fee any time you buy something priced in a foreign currency, whether or not you buy it online.

I'd pre-purchase online if the price was lower, if I wanted the security of knowing I'd taken care of something in advance, or if I didn't want the hassle of standing in a queue to buy something.

The trade off, of course, is that if you change your mind about using a ticket, etc., once you're in Ireland, you lose a bit of money.

I think many people here would suggest that, once you're in Ireland, you use the credit card for large purchases -- hotel, car, etc. -- and withdraw cash with an ATM for everything else.

Just let the issuers of your credit/ATM cards know when you will be traveling so they don't flag your first attempt to use a card in Ireland as potential fraud and freeze your account. Also, I believe European ATM and bank machines often can't handle PIN's that include letters or the number 'zero'. I change my PIN's to four digits of the numbers one through nine and have had no problems.

I would get a Capital One Visa for the trip. They don't charge the extra fee for overseas purchases. I don't like carrying a lot of cash, and I charged most things on my last trip overseas. You will need to call them before you leave the states to let them know that you will be making lots of charges from out of the country, and you won't have any problems.

For our trip to the UK last month I pre-purchased tickets that would allow us to avoid notoriously long lines (Tower of London) or that might not have been available had we waited til we arrived (performance at Shakespeare's Globe). Since you'll get stuck with an international transaction fee whether you buy online or not, I'd say convenience and/or online discounts are the main considerations. For the B & B's most of the ones we stayed at required a CC to hold the reso, but when there we paid cash, as most all of the B & Bs charge a few percent more to pay with a CC.

"I believe European ATM and bank machines often can't handle PIN's that include letters or the number 'zero'."

From my experience this is not correct. My debit card PIN contains a zero and it has never been rejected by a European ATM.

Also, if your PIN contains letters, all you have to do is learn the equivalent numbers by looking at your home bank's ATM keypads.