As the price of euro's

Not sure exactly what your question is. But see the other thread on conversion rates. Trying to guess/predict future currency rates is not for amatuers. And the cost to buy euros in the US is between 5-10% above the interbank rate. The cost to get euros from an ATM in Europe is generally 1-3% depending on your bank's fees. So buying euros ahead of time is unlikely to save you any money even if the rates go up.

And, of course, there is a "cost" to holding euros instead of having the money gaining any interest (yes, I know - what interest?) in a bank account until you need it.

Nancy, what interest? Yes. LOL At least it's not like the hyperinflation days of Brazil where you spent all your money on payday because tomorrow you could buy less with it. I can't remember the exact inflation rate but I think at one point it was more than fifty percent each month.