This would only be arbitraging if you were buying something on one card and returning it on another card. It's not arbitrage if you're not making a profit, it's just saving.
Great point! Wrong choice in words; will edit the post to make better sense. Also looks like someone else edited the title of this post on YC. Any idea how to change it back?
1% of oversee spending may be to little benefit for the cost:
1. Get more than one card with zero foreign transaction fees. Make sure you won't get charged yearly fee on those.
2. On every transaction, check the rate on smarthphone. Oh, you want to buy $3 coffee, let me check my rate to see if I can save $0.03.
3. More cards is more monitoring hassle. Harder to track, more hassle if they get stolen and you need to block them all. Also payback program tracking is much harder.
4. Same with fees and interests. More card is more likely that you miss some payments and get charged interests/overdraft. One incident and you whole savings can go away. Even with autopayment you need to make sure you balance your accounts.
I think, but I'm not sure, that you're overstating the complication. Looking at your four steps:
1. Everyone should have two credit cards. You don't want a single point of failure (mistaken fraud freeze, for example.)
2. You only check every day, not every transaction.
3. Again, I argue you should have two (Visa + Mastercard)
4. Again. You're just trying to make things sound hard by repeating the same thing.
So. Have two cards. Make sure they autopay themselves. The only new work is checking the exchange rates once a day.
You also need to factor in any foreign currency fees your card issuer imposes. For example, in the UK, most banks impose a "non-sterling transaction fee" of 2.75-2.99% on transactions in a foreign currency.
There's a UK startup called Revolut - www.revolut.com - which allows you to hold GBP, USD and EUR on the same (pre-paid debit) card and convert money between them at mid-market rates, using an app.
It's pretty slick - I've literally stood at the counter, converting GBP to USD while the clerk rang up my purchase, then handed the card to the clerk and had the notification hit my phone seconds after he swiped.
It's sad that I have to say this in 2015, but the cheapest way to deal with money oversees is to... use cash as much as possible. It's not as convenient (although, everybody takes cash, credit cards - depends on where you go...), but taking a wad of cash for trips <= 1 week or making weekly withdrawals for travels longer than that is usually by far the cheapest option.
As somebody who travels a lot credit cards are much, much cheaper than cash. It's not even close. Banks / exchange shops have commissions (baked into the exchange rate) from 2.5% to 5%.
My credit card charges $5 flat fee to take out cash, gives spot forex rates, and gives me 1% cashback on purchases. So if I take out $500 cash and spend $500 directly on the card I pay zero fees versus the $25-$50 in fees I'd spend dealing with $1000 cash.
I was wrong, it's 1% per cash advance with a minimum of $5. I've never taken more than $500 in cash out at a time so that's how I remembered it. Also, the above calculations assume you overpay the card beforehand so you don't incur interest charges.
I've found that cards get better exchange rates than converting cash. Sometimes several dozen percentage points better. However, if you pull the local currency out of an ATM, you get the card network's exchange rate, and at worst an ATM fee (if any).
Not in my experience (travelling to Budapest). Withdrawing EUR and converting to HUF in a local shop gave us a better rate than withdrawing HUF directly. Never buy stuff with EUR, though!
Agreed. That's what I've done for the past few years. If you get a good rate ahead of time, you're set. The main reason I do it, though, is I had numerous bad experiences with banks and credit cards blocking me over and over when I went to buy things overseas and I was sick of that - cash is king (if you can cope with the safety aspects).
Without real-time rates available from multiple networks, this relies on that back-tested effect that the card with the better rate tends to persist for several days; is there a reason to be confident that will continue? Not that there's much risk if it doesn't, but you could well just be wasting your time.
Because even with no fees, the rate your card uses to turn USD into whatevers will vary from card to card. If you're not paying an up front transaction fee, you're almost certainly getting rinsed on the rate offered.
Even among cards that generally use the mid market rate, the time they set the rate and their source will often differ, resulting in the differences mentioned in the OP. So if you feel it's worth your time, and if you can get up to date rates, you can still save a bit by using the card with the best rate on a given day.
Nice cost-comparison tool though :)