German phrase
Welcher Kurs gilt bei ~?
Meaning
Which exchange rate applies to ___?
When to use it
Asks which rate applies. Use it to compare rates for different payment methods.
Example dialogue
Welcher Kurs gilt bei Kreditkartenzahlungen?
Which exchange rate applies to credit card payments?
Das hängt vom Anbieter ab; meist gilt der Interbanken-Kurs.
That depends on the provider; usually, the interbank rate applies.