No doubt about it, the so-called "dynamic" currency charge is a rip. Why not just call it foreign merchant's tourist overcharge fee?

Anyhow, just back from Spain and some of my charges have arrived on the latest bill.

I noted mysterious charges for "Eci" which turned out to be El Cortes Ingles the biggest store there. Eci, whenever I used my US credit card there, presented me with a slip that gave me a choice as to being charge in $s or Euros. $ charge would it stated, incur a 2.5% forex fee (obviously meant to sound cheaper than the 3% credit card fee). I did not bite and see that all my charges came though in Euros.

It was quite difficult to get into this the first time with a non-English speaking clerk while I was in jet lag shock. She insisted I had to do something (choose currency on slip), but I didn't know what she was talking about. Apparently, at Eci, if you make no choice, the billing comes in Euros.

Thanks to OP for providing some hard data on this odious practice's costs.