CathHarmony, I've owned a pair of ultra cheap roller suitcases ... they are great for one trip. Just unpack and throw them away when you get home!
I've never seen anything quite that cheap in Switzerland, but I'd start by looking at my favourite cheap shops in Langnau or Adliswil. I'd also check the brocki for someone's good quality discard. Failing that, hallo Konstanz!