Yes it is a legal requirement to have the swiss vignette and the swiss police will gladly fine you quite heavily for not having one but the cheaper option is to buy one whenever your there tape it to your windscreen DONT remove it from its backing paper and sell it on ebay on your return or buy one from ebay which also hasn't had its backing paper removed. If you are selling one on ebay go for a 3 day auction as its against ebay rules to sell the vignette but I've sold 3 vignettes on ebay so far or PM someone who is selling a vignette on ebay with a buy it now price including P&P and then they normally get back to you whenever ebay remove their item that's also worked for me
P.s. I've never paid more than £20 and that includes postage for a swiss vignette whenever buying off ebay
