(A nod to the thread questioning why people air duvets out on balconies. )
I mostly buy my sheets from Landsend in the US, deliverable to Switzerland with the inexpensive pre-paid customs duty option via BorderFree.
I have US sized mattresses, UK/EU fixed sheets don't fit so I might as well buy all sheets as a set. Not to mention LE's high thread count/non-wrinkling sheets are of a quality far exceeding anything I have found for sale in Switzerland, at a significant savings. Stay way from low thread count, and unless you want to spend your life ironing, stay away from wrinkly fabrics.
I buy on sale, and take advantage of frequent special offers for further reductions. Just the other day I scooped up a sheet set regularly priced at ca 250 for ca. 60. A steal even with shipping and customs fees.
https://www.landsend.com/shop/home-b...case_-20150901 .
(LE has UK and DE sites, but these do not carry bedding or most of LE's home products.)
Other US retailers are LLBean, Garnet Hill, Company Store, and PotteryBarn, but they don't tend to have the great sales that LE does.