Why would you bring U.S. dollars to Germany? Do not exchange money at your U.S.bank or any bank in a foreign country

The easiest, simplest way is:
1. Make sure that you have an ATM/Debit card from your U.S. bank.
2. Notify your bank prior to leaving as to which foreign countries you’ll be visiting and the dates.
3. Get the business card of your bank’s branch manager that has their phone number and email address.
(2 & 3 are based on past experience. Was not able to use my ATM card on two different trips to Germany. Wasn’t a problem during the same trip when I drove into Switzerland and Austria and used the card. According to my bank, they had experienced an uptick in fraud at German ATMs, so they had a hold on U.S. ATM cards at the time. On my second trip, I just emailed my branch manager and he had my card cleared for use.)

4. After you get to FRA, use one of the many bank ATM machines to withdraw Euros.

You will more than likely have to pay your bank a fee for each withdrawal, so don’t keep making €100 withdrawals. Make larger withdrawals. The bank service fees aren’t onerous. If you’re too concerned with the bank service fees, than wait until you’ve saved more money for your trip before going. Life’s too short to waste worrying about such a small thing.

5. Apply for a credit card with no foreign transaction fees.

Enjoy your trip.

Which is why I also said to bring a “no foreign transaction fee” credit card. So, as mentioned above, 2 cards, not one. One ATM/Debit card and one no fee credit card. If they want to be more comfortable, bring another credit card or 2. If they want to bring some cash, so be it.

I frequently fly overseas with less than $100 USD because I’ve never needed USD. When I first started traveling to Europe I used to exchange money in the European banks - before I knew better. A real noob mistake. The OP will probably arrive at FRA in the morning and if he/she tries an ATM immediately, they will know if the ATM card works. If not, shoot an email to their branch manager and the card should be working by mid-afternoon in Europe. In the meantime, they can use their credit card, if necessary. This is all based on my real world experiences. YMMV.

But wouldn't it be a better idea to bring Euro? Shouldn't be a problem to get them at home.

I am not aware of any banks that do not charge to use their ATMs. Make sure that you always use a bank owned ATM. Independently owned ATMs are a ripoff. Just resolve to yourself that you will be paying some fee to use an ATM and get on with enjoying your trip. As the old saying goes, “There is no free lunch.”.

I just checked my latest bank statement which included my last trip. For one withdrawal in Austria, I paid $4.33; another in Switzerland was $4.06. Really insignificant amounts.