On my recent trip to Sardinia, Italy the issue of money seemed to invade every conversation — how to exchange it, where to exchange it, what’s the best rate, how much is that in euros??? I’m ashamed to say (as the travel expert in the group) that I didn’t always have the answers. So when I got back I decided to bone up on this topic and now I will share this knowledge with you!

Here’s my top four money tips for exchanging money when traveling abroad:

1) Get Cash from the ATM

I knew that I would need money as soon as we arrived in Italy for transportation, food, and other things. So I exchanged my money in the airport in the U.S. To get the best rate and avoid fees I had to exchange a lot of it–around $1000. #moneyfail

Later I read that the exchange counters in the airport are the worse possible place to exchange your money. You can lose up to 18 percent. To some degree I knew this but I really needed some cash.

What I should have done is waited until I arrived in Italy, found an ATM in the airport, and used my debit card to take out the cash. You’ll probably be charged between $2 to $5 worth of fees, but you’ll still make out better than the currency exchange counter, local bank, hotel exchange desk, or money exchange place. Steer clear of the Travelex, Euronet, and Forex machines which will eat into your savings.

If for some reason you don’t want to use the ATM for cash, your next best option is the local post office. They generally have the next best rate, however what you save in money you’ll lose in time. Who hasn’t stood in a post office line before? In Italy, I waited in line to exchange money at the post office for nearly an hour. Another downside–don’t expect the attendant to speak your language. These folks may not be used to dealing with tourists so make sure you know how to say what you want in the local language.

2) When to Use Credit Cards

It’s helpful to bring a credit card along on your trip for many reasons. For one, if there’s an emergency and you need a lot of money, a card can be your savior. But otherwise, it may be best to use your card for bigger purchases and save your cash for places that don’t accept credit. Jewelry, expensive souvenirs, large meals, and hotel bills are perfect for the plastic.

Save your cash for markets, transportation, snacks, entry fees, etc. which often don’t take cards. You’ll want to alert your credit card company ahead of time about your travels so that they don’t shut down your card based on what they might consider suspicious activity. Lastly, be smart about what card you take with you on your vacation. Opt for a card that doesn’t charge international transaction fees, for example, Capital One and American Express Platinum.

3. Know the Conversion Rate By Heart

I suck at math–really, really suck. But it’s important to be able to figure out how much something is worth in American dollars in the local currency. So if the exchange rate is €1 = $1.40, for example, you should be able to determine that a €5 gelato costs five times $1.40, or about $7. Ten euros is about $14, and €250 = $350 (figure about 250 plus a little less than one-half). Knowing this is crucial if you plan not to be swindled by every vendor and if you’re on a budget.

4) Where to Change Money Back

The best answer I could find concerning where to change your money back is at your bank back in the U.S. However, if you need that money right away upon arriving back home, then it’s more convenient to switch it right in the airport at one of those currency exchange booths. You might not get the best rate but you’ll have the money at your disposal right away.