Just clarifying what I said earlier. I pay for these purchases with Paypal in CHF (as that is that is the currency on the vendor's website), paypal shows the exact amount in CHF, and my credit card bill shows the exact amount in CHF. So I think for these kind of purchases, paypal works.

What is interesting about Campz and Bikester is that when you have to return items, you return them to a St. Gallen address.